Spring (season)
Spring is one of the fourtemperate season, the transition period between winter and summer . Spring and "springtime" refer to the season, and broadly to ideas of rebirth, renewal and regrowth. The specific definition of "spring" as a season differs, however, among scientific disciplines such as astronomy and meteorology, and in cultural and human terms. The exact definitions are explored below.
As it refers to climate and the Earth's tilt relative to the sun, spring days are close to 12 hours long with day length increasing as the season progresses.
Definition
Meteorologists generally define four seasons in many climatic areas, winter, spring, summer and autumn (or fall). These are demarcated by the values of their average temperatures on a monthly basis, with each season lasting three months. The three warmest months are by definition summer, the three coldest months are winter, and the intervening gaps are spring and autumn. Spring, when defined in this manner, can start on different dates in different regions. In terms of complete months, in most North Temperate Zone locations, spring months are March, April and May (Summer is June, July, August; autumn is September, October, November; winter is December, January, February). The vast majority of South Temperate Zone locations will have opposing seasons with spring in September, October and November.
Astronomically, the vernal equinox (usually 20 March in the Northern Hemisphere, and 22 September in the Southern Hemisphere), should be the middle of spring (based on the angle of the sun and insolation) and the summer solstice (usually 21 June in the Northern Hemisphere and 21 December in the Southern Hemisphere) should be the middle of summer (because the sun is at its highest), but daytime temperatures lag behind insolation by several weeks because the earth and sea have thermal latency and take time to warm up.
Some cultures, such as those that devised the Celtic and East Asian calendars, call the spring equinox "mid-spring", but others (especially in the USA and sometimes in England) regard it as the "first day of spring". For most temperate regions, signs of spring appear long before the middle of March, but the folklore of 21 March being the "first day of spring" persists, and 21 June as the "first day of summer" is common in the USA. In South Africa, Australia and New Zealand, spring begins on 1 September, and has no relation to the vernal equinox
In East Asian Solar term, spring begins on 4 February and ends on 5 May. Similarly, according to the Celtic tradition, which is based solely on daylight and the strength of the noon sun, spring begins in early February (near Imbolc or Candlemas) and continues until early May (Beltane).
The phenological definition of spring relates to indicators, the blossoming of a range of plant species, and the activities of animals, or the special smell of soil that has reached the temperature for micro flora to flourish. It therefore varies according to the climate and according to the specific weather of a particular year.
Events
In spring, the axis of the Earth is increasing its tilt toward the Sun and the length of daylight rapidly increases for the relevant hemisphere. The hemisphere begins to warm significantly causing new plant growth to "spring forth," giving the season its name. Snow, if a normal part of winter, begins to melt, and streams swell with runoff. Frosts, if a normal part of winter, become less severe. Temperate climates have no snow and rare frosts, the air and ground temperature increases more rapidly. Many flowering plants bloom this time of year, in a long succession sometimes beginning even if snow is still on the ground, continuing into early summer. In normally snowless areas "spring" may begin as early as February (Northern Hemisphere) heralded by the blooming of deciduous magnolias, cherries, and quince, or August (Southern Hemisphere) in the same way. Subtropical and tropical areas have climates better described in terms of other seasons, e.g. dry or wet, or monsoonal, or cyclonic. Often the cultures have locally defined names for seasons which have little equivalence to the terms originating in Europe. Many temperate areas have a dry spring, and wet autumn (fall), which brings about flowering in this season more consistent with the need for water as well as warmth. Subarctic areas may not experience "spring" at all until May or even June, or December in the outer Antarctic.
While spring is a result of the warmth caused by the turning of the Earth's axis, the weather in many parts of the world is overlain by events which appear very erratic taken on a year-to-year basis. The rainfall in spring (or any season) follows trends more related to longer cycles or events created by ocean currents and ocean temperatures. Good and well-researched examples are the El Niño effect and the Southern Oscillation Index.
Unstable weather may more often occur during spring, when warm air begins on occasions to invade from lower latitudes, while cold air is still pushing on occasions from the Polar regions. Flooding is also most common in and near mountainous areas during this time of year because of snowmelt, accelerated by warm rains. In the United States, Tornado Alley is most active this time of year, especially since the Rocky Mountains prevent the surging hot and cold air masses from spreading eastward and instead force them into direct conflict. Besides tornadoes, supercell thunderstorms can also produce dangerously large hail and very high winds, for which a severe thunderstorm warning or tornado warning is usually issued. Even more so than in winter, the jet streams play an important role in unstable and severe weather in the springtime in the Northern Hemisphere.
In recent decades season creep has been observed, which means that many phenological signs of spring are occurring earlier in many regions by a couple of days per decade.
Spring is seen as a time of growth, renewal, of new life (both plant and animal) being born. The term is also used more generally as a metaphor for the start of better times, as in the Prague Spring. Spring in the Southern Hemisphere is different in several significant ways to that of the Northern Hemisphere. This is because: there is no land bridge between Southern Hemisphere countries and the Antarctic zone capable of bringing in cold air without the temperature-mitigating effects of extensive tracts of water; the vastly greater amount of ocean in the Southern Hemisphere at all latitudes; at this time in Earth's geologic history the Earth has an orbit which brings it in closer to the Southern Hemisphere for its warmer seasons; there is a circumpolar flow of air (the roaring 40s and 50s) uninterrupted by large land masses; no equivalent jet streams; and the peculiarities of the reversing ocean currents in the Pacific.
Festivals
Mesopotamia
Akitu (Sumerian Akiti-šekinku "cutting of barley", Akiti-šununum "sowing of barley", Babylonian rêš-šattim "head of the year") was a spring festival in ancient Mesopotamia. The name is from the Sumerian for "barley", originally marking two festivals celebrating the beginning of each of the two half-years of the Sumerian calendar, marking the sowing of barley in autumn and the cutting of barley in spring, in the month of Nisannu (Aries). In Babylonian religion it came to be dedicated to Marduk's victory over Tiamat.
Afghanistan
The first day of spring is the beginning of the new year, Nowruz, in the Solar Hijri Calendar. Nowruz (also Naw-Rúz, Norooz, Newroz, Navroj, and many other variants) which means "New Day" in Persian, marks an important traditional holiday festival celebrated in Afghanistan as well as in many other countries such as Azerbaijan, Iran and Tajikistan.
Australia
The annual Spring Racing Carnival of thoroughbred horse racing events is held in Melbourne in October and November, with large crowds attending. The Melbourne Cup, held on the first Tuesday of November, is Australia's premier horse race and is recognised as a public holiday in the state of Victoria. It is also referred to as The race that stops a nation.
Persia (Iran)
The first day of spring (celebrated on the day of the astronomical vernal equinox, which usually occurs on 21 March or the previous or following day depending on where it is observed) is the beginning of the new year, Nowruz, in the Iranian calendar. Nowruz (also Naw-Rúz, Norooz, Newroz, Navroj, and many other variants)which means "New Day" in Persian language, marks an important traditional holiday festival celebrated in Iran as well as in many other countries with a significant population from one of various Iranian peoples, such as Azerbaijan, Afghanistan and Tajikistan, and by Kurdish communities in Turkey and Iraq and elsewhere
May Day
1 May is the date of several public holidays.[4] In many countries, May Day is synonymous with International Workers' Day, or Labour Day, which celebrates the social and economic achievements of the labour movement. As a day of celebration the holiday has ancient origins, and it can relate to many customs that have survived into modern times. Many of these customs are due to May Day being a cross-quarter day, meaning that (in the Northern Hemisphere where it is almost exclusively celebrated) it falls approximately halfway between the spring equinox and summer solstice. In the Celtic tradition, this date marked the end of Spring and the beginning of Summer.
Easter
Easter is the most important religious feast in the Christian liturgical year.[5] Christians believe that Jesus was resurrected from the dead on the "third day"[6] (two days after his crucifixion), and celebrate this resurrection on Easter Day, two days after Good Friday. The date of Easter varies between 22 March and 25 April in Western tradition, and between 4 April and 8 May in Eastern Christianity.
India
Holi,- the festival of colors - celebrated at the end of the winter season on the last full moon of the lunar month Phagwah (February/March), is the most vibrant festival of colours celebrated by Hindus in North India. People throw water and apply colour powders on each other.Vasant Panchami is celebrated in North India on the fifth day of the Indian month Magh (January–February), the first day of spring. Sankranthi is celebrated in South India (Andhra Pradesh) in mid January to mark the beginning of spring season.
Chinese New Year
The Chinese Spring Festival is the most important of the traditional Chinese holidays. It is often called the Lunar New Year, especially by people in mainland China, Taiwan, Singapore and Malaysia. The festival traditionally begins on the first day of the first month (Chinese: 正月; pinyin: zhēng yuè) in the Chinese calendar and ends on the 15th; this day is called Lantern Festival. Chinese New Year's Eve is known as Chúxī. It literally means "Year-pass Eve". The usual starting date is the second new moon after the winter solstice, i.e. between mid-January and mid-February in the Gregorian calendar.
Vietnam
Vietnamese use the traditional lunar as well as the modern solar calendar. They celebrate Vietnamese New Year in late January or early February is also known as the beginning of Spring. The lunar calendar is used mainly to divide the year into seasons for agriculture purposes. In the old days, the celebration used to last the entire month of January of the lunar calendar. Traditionally, firecrackers are used on New Year's Eve, or đêm giao thừa in Vietnamese, to scare away bad spirits and souls.
Autumn season
Autumn (also known as fall in American English) is one of the four temperate seasons. Autumn marks the transition from summer into winter, usually in March (Southern Hemisphere) or September (Northern Hemisphere) when the arrival of night becomes noticeably earlier.
The equinoxes might be expected to be in the middle of their respective seasons, but temperature lag (caused by the thermal latency of the ground and sea) means that seasons appear later than dates calculated from a purely astronomical perspective. The actual lag varies with region, so some cultures regard the autumnal equinox as "mid-autumn" whilst others treat it as the start of autumn (as shown in the above table).
Autumn starts on or around 8 August and ends on about 7 November in traditional East Asian solar term.
In Ireland, the autumn months according to the national meteorological service, Met Éireann, are September, October and November.[4] However, according to the Irish Calendar which is based on ancient Celtic traditions, autumn lasts throughout the months of August, September, and October, or possibly a few days later, depending on tradition. In Australia autumn officially begins on 1 March and ends 31 May.[5] The vast diversity of the ecological zones of the Australian continent renders the rigid American seasonal calendar an imposed cultural concept rather than relevant to climactic conditions. The seasonal cycles as named and described by the various indigenous Aboriginal peoples of Australia differ substantially from one another according to their local geographical and ecological environment and are intricately dependent on local environmental events and resources.[6]
Etymology
The word autumn comes from the Old French word autompne (automne in modern French), and was later normalised to the original Latin word autumnus.[7] There are rare examples of its use as early as the 12th century, but it became common by the 16th century.
Before the 16th century, harvest was the term usually used to refer to the season. However, as more people gradually moved from working the land to living in towns (especially those who could read and write, the only people whose use of language we now know), the word harvest lost its reference to the time of year and came to refer only to the actual activity of reaping, and autumn, as well as fall, began to replace it as a reference to the season.[8][9]
The alternative word fall is now mostly a North American English word for the season. It traces its origins to old Germanic languages. The exact derivation is unclear, the Old English fiæll or feallan and the Old Norse fall all being possible candidates. However, these words all have the meaning "to fall from a height" and are clearly derived either from a common root or from each other. The term came to denote the season in 16th century England, a contraction of Middle English expressions like "fall of the leaf" and "fall of the year".[10]
During the 17th century, English emigration to the colonies in North America was at its peak, and the new settlers took their language with them. While the term fall gradually became obsolete in Britain, it became the more common term in North America, where autumn is nonetheless preferred in scientific and often in literary contexts.[citation needed]
In popular culture
Harvest association
Association with the transition from warm to cold weather, and its related status as the season of the primary harvest, has dominated its themes and popular images. In Western cultures, personifications of autumn are usually pretty, well-fed females adorned with fruits, vegetables and grains that ripen at this time. Most ancient cultures featured autumnal celebrations of the harvest, often the most important on their calendars. Still extant echoes of these celebrations are found in the mid-autumn Thanksgiving holiday of the United States, and the Jewish Sukkot holiday with its roots as a full moon harvest festival of "tabernacles" (huts wherein the harvest was processed and which later gained religious significance). There are also the many North American Indian festivals tied to harvest of autumnally ripe foods gathered in the wild, the Chinese Mid-Autumn or Moon festival, and many others. The predominant mood of these autumnal celebrations is a gladness for the fruits of the earth mixed with a certain melancholy linked to the imminent arrival of harsh weather.
This view is presented in English poet John Keats' poem To Autumn, where he describes the season as a time of bounteous fecundity, a time of 'mellow fruitfulness'.
Melancholy association
Autumn in poetry has often been associated with melancholy. The possibilities of summer are gone, and the chill of winter is on the horizon. Skies turn grey, and people turn inward, both physically and mentally.[11] Rainer Maria Rilke, a German poet, has expressed such sentiments in one of his most famous poems, Herbsttag (Autumn Day), which reads
Who now has no house, will not build one (anymore).
Who now is alone, will remain so for long,
will wake, and read, and write long letters
and back and forth on the boulevards
will restlessly wander, while the leaves blow.
Similar examples may be found in Irish poet William Butler Yeats' poem The Wild Swans at Coole where the maturing season that the poet observes symbolically represents his own aging self. Like the natural world that he observes he too has reached his prime and now must look forward to the inevitability of old age and death. French poet Paul Verlaine's "Chanson d'automne" ("Autumn Song") is likewise characterized by strong, painful feelings of sorrow. Keats' To Autumn, written in September 1819, echoes this sense of melancholic reflection, but also emphasises the lush abundance of the season.
Season of mists and mellow fruitfulness,
Close bosom-friend of the maturing sun;
Conspiring with him how to load and bless
With fruit the vines that round the thatch-eves run;
To bend with apples the moss’d cottage-trees,
And fill all fruit with ripeness to the core;'
Other associations
Autumn is also associated with the Halloween season (which in turn was influenced by Samhain, a Celtic autumn festival),
and with it a widespread marketing campaign that promotes it. The television, film, book, costume, home decoration, and confectionery industries use this time of year to promote products closely associated with such holiday, with promotions going from early September to 31 October, since their themes rapidly lose strength once the holiday ends, and advertising starts concentrating on Christmas.
Since 1997, Autumn has been one of the top 100 names for girls in the United States.
In Indian mythology, autumn is considered to be the preferred season for the goddess of learning Saraswati, who is also known by the name of "goddess of autumn" (Sharada).
Tourism
Although color change in leaves occurs wherever deciduous trees are found, colored autumn foliage is most famously noted in three regions of the world: most of Canada and the United States, Eastern Asia (including China, Korea, and Japan), and Europe.
Eastern Canada and the New England region of the United States are famous for the brilliance of their autumnal foliage, and this attracts major tourism (worth billions of US$) for the regions.
Summer
Summer is the warmest of the four temperate seasons, between spring and autumn. It is marked by the longest days and shortest nights. The seasons start on different dates in different cultures based on astronomy and regional meteorology. However, when it is summer in the southern hemisphere it is winter in the northern hemisphere, and vice versa. In areas of the tropics and subtropics, the wet season occurs during the summer. Tropical cyclones develop and roam the tropical and subtropical oceans during the summer. In the interior of continents, thunderstorms are most likely to produce hail during the afternoon and evening. Schools and universities have a summer break to take advantage of the warmer weather and longer days.
Timing
From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons, but a variable seasonal lag means that the meteorological start of the season, which is based on average temperature patterns, occurs several weeks later than the start of the astronomical season.[1] According to meteorologists, summer extends for the whole months of June, July and August in the northern hemisphere and the whole months of December, January and February in the southern hemisphere.[2] This meteorological definition of summer also aligns with the commonly viewed notion of summer as the season with the longest (and warmest) days of the year, in which daylight predominates. From the astronomical perspective, days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring.
The meteorological reckoning of seasons is used in Austria, Denmark and the former USSR; it is also used by many in the United Kingdom, where summer is thought of as extending from mid-May to mid-August. The definition based on equinox to solstice is more frequently used in the United States where a temperature lag of up to half a season is common[3].
Elsewhere, however, Solstices and equinoxes are taken to mark the mid-points, not the beginnings, of the seasons. In Chinese astronomy, for example, summer starts on or around 5 May, with the jiéqì (solar term) known as lìxià (立夏), i.e. "establishment of summer", and it ends on or around 6 August. An example of Western usage would be William Shakespeare's A Midsummer Night's Dream, where the play takes place over the shortest night of the year, which is the summer solstice.
In Ireland, the summer months according to the national meteorological service, Met Eireann, are June, July and August. However, according to the Irish Calendar summer begins 1 May and ends 1 August. School textbooks in Ireland follow the cultural norm of summer commencing on 1 May rather than the meteorological definition of 1 June.
In southern and southeast Asia, where the monsoon occurs, summer is more generally defined as lasting from March to May/early June, their warmest time of the year, ending with the onset of the monsoon rains.
In coastal areas of the United States, summer season begins on The Day after Memorial Day and ends on The Day Before Autumn Equinox. Likewise, another set of pop-cultural reference points for summer in the USA is the time when elementary and secondary schools close down for the "summer vacation". This period usually lasts from around early to mid June until around late August to early September, depending on where the school is located. In the United States, summer is often fixed as the period from the summer solstice (around June 20 or 21, depending on the year; for 2010, it is June 21) to the fall equinox.[4][5][6][7]
Weather
Summer is traditionally associated with hot dry weather, but this does not occur in all regions. The wet season occurs during summer across many parts of the tropics and subtropics. Where the wet season is associated with a seasonal shift in the prevailing winds, it is known as a monsoon. The wet season is the main period of vegetation growth within the savanna climate regime. However, this also means that wet season is a time for food shortages before crops reach their full maturity. This causes seasonal weight changes for people in developing countries, with a drop occurring during the wet season until the time of the first harvest, when weights rebound. Malaria incidence increases during periods of high temperature and heavy rainfall.
The onset of the rainy season signals the departure of the Monarch butterfly from Mexico. Tropical species of butterflies show larger dot markings on their wings to fend off possible predators and are more active during the wet season than the dry season. Within the tropics and warmer areas of the subtropics, decreased salinity of near shore wetlands due to the rains causes an increase in crocodile nesting. Other species, such as the arroyo toad, spawn within the couple months after the seasonal rains.[16] Armadillos and rattlesnakes seek higher ground.
In the Northern Atlantic Ocean, a distinct tropical cyclone season occurs from 1 June to 30 November, sharply peaking from late August through September.[18] The statistical peak of the Atlantic hurricane season is 10 September. The Northeast Pacific Ocean has a broader period of activity, but in a similar time frame to the Atlantic.[19] The Northwest Pacific sees tropical cyclones year-round, with a minimum in February and March and a peak in early September. In the North Indian basin, storms are most common from April to December, with peaks in May and November.[18] In the Southern Hemisphere, the tropical cyclone year begins on 1 July and runs all year round and encompasses the tropical cyclone seasons which run from 1 November until the end of April with peaks in mid-February to early March.
Across interior North America, cumulonimbus clouds produce hail between the months of March and October during the afternoon and evening hours, with the bulk of the occurrences from May through September. Cheyenne, Wyoming is North America's most hail-prone city with an average of nine to ten hailstorms per season.
Construction
In higher latitude locations, summer is the time for road resurfacing, as winter ice and snow leaves potholes behind in the pavement due to the expansion and contraction of ice and snow during the winter months. Construction jobs tend to have minimum temperature requirements in order for work to be accomplished, such as the laying of concrete. This is because materials like concrete take increasingly longer to dry within cold temperature regimes. Also, working within warmer weather regimes is done to prevent expansion of ice within the new material, which decreases its potential strength and integrity.
School break
In most countries children are out of school during this time of year for summer holidays, although dates vary. In the Northern hemisphere, some begin as early as mid-May, although in England and Wales, school ends in mid- to late July. In the Southern hemisphere, school holiday dates include the major holidays of Christmas and New Year's Day. Summer school holidays in Australia begin a few weeks before Christmas and end in late January to mid-February, with the dates varying in different states.
Activities
People take advantage of the warmer temperatures by spending more time outdoors during the summer. Activities such as traveling to the beach and picnics occur during summer months. Sports such as cricket, volleyball, skateboarding, baseball, softball, soccer, tennis, and football are played. Water skiing is a uniquely summer sport, which is done when waters approach their warmest of the year.
Wet /rainy seasons
The wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region falls.[1] The term green season is also sometimes used as a euphemism by tourist authorities.[2] Areas with wet seasons are dispersed across portions of the tropics and subtropics.[3] In contrast to areas with savanna climates and monsoon regimes, mediterranean climates have wet winters and dry summers. Tropical rainforests technically do not have dry or wet seasons, since their rainfall is equally distributed through the year.[4] Some areas with pronounced rainy seasons will see a break in rainfall mid-season when the intertropical convergence zone or monsoon trough move poleward of their location during the middle of the warm season.[5]
When the wet season occurs during the warm season, or summer, precipitation falls mainly during the late afternoon and early evening hours. The wet season is a time when air quality improves, freshwater quality improves, and vegetation grows significantly, leading to crop yields late in the season. Floods cause rivers to overflow their banks, and some animals to retreat to higher ground. Soil nutrients diminish and erosion increases. The incidence of malaria increases in areas where the rainy season coincides with high temperatures. Animals have adaptation and survival strategies for the wetter regime. Unfortunately, the previous dry season leads to food shortages into the wet season, as the crops have yet to mature.
Character of the rainfall
The wet, or rainy, season covers one or more months when most of the average annual rainfall in a region falls. The term green season is also sometimes used by those in tourism. In areas where the heavy rainfall is associated with a wind shift, the wet season becomes known as the monsoon.[6] Since rainfall during the wet season is predominantly due to daytime heating which leads to diurnal thunderstorm activity within a pre-existing moist airmass, rainfall is mainly focused during the late afternoon and early evening hours within savannah and monsoon regimes. This also leads to much of the total rainfall each day falling during the initial minutes of the downpour,[5] before the storms mature into their stratiform stage.[7] While most locations have only one wet season, areas of the tropics can experience two wet seasons as the monsoon trough, or Intertropical Convergence Zone, can pass over locations in the tropics twice per year. Since rain forests have equitable rainfall throughout the year, they do not technically have a wet season.[4]
The situation is different for locations within the Mediterranean climate regime. In the western United States, during the cold season from September through May, extratropical cyclones from the Pacific ocean move inland into the region due to a southward migration of the jet stream during the cold season. This shift in the jet stream brings much of the annual precipitation to the region,[8] and also brings the potential for heavy rain and strong low pressure systems.[9] The peninsula of Italy experiences very similar weather to the western United States in this regard.[10]
Areas impacted
Areas with a savannah climate in Sub-Saharan Africa, such as Ghana, Burkina Faso,[11][12] Darfur,[13] Eritrea,[14] Ethiopia,[15] and Botswana have a distinct rainy season.[16] Also within the savannah climate regime, Florida and East Texas have a rainy season.[17][18] Monsoon regions include southeast Asia (including Indonesia),[19] northern sections of Australia's Northern Territory,[20] Polynesia,[21] Central America,[22] western and southern Mexico,[23] the Desert Southwest of the United States,[8], southern Guyana,[24] portions of northeast Brazil.[25]
Northern Guyana experiences two wet seasons: one in late spring and the other in early winter.[24] In western Africa, there are two rainy seasons across southern sections with only one across the north.[26] Within the Mediterranean climate regime, the west coast of the United States and the Mediterranean coastline of Italy, Greece,[27] and Turkey experience a wet season in the winter months.[28] At the boundary between the Mediterranean and monsoon climates lies the Sonoran desert, which receives the two rainy seasons associated with each climate regime.[29]
Effects
In tropical areas, when the monsoon arrives daytime high temperatures drop and overnight low temperatures increase.[30] During the wet season, a combination of heavy rainfall and in some areas, such as Hong Kong, a wind more off the ocean, significantly improve air quality.[31] In Brazil, the wet season is correlated to weaker trade winds off the ocean.[25] The pH level of water becomes more balanced due to the charging of local aquifers during the wet season.[32] Water also softens, as desolved materials lower in concentration during the rainy season.[33] Erosion is also increased during rainy periods.[5] Arroyos that are dry at other times of the year fill with runoff, in some cases with water as deep as 10 feet (3.0 m).[34] Leaching of soils during periods of heavy rainfall depletes nutrients.[34] The excessive runoff from land masses significantly impacts nearby ocean areas, which are more stratified, or less mixed, due to stronger surface currents forced by the heavy rainfall runoff.[35]
Floods
Widespread flooding can occur if rainfall becomes excessive,[36] which can lead to landslides and mudflows in mountainous areas.[37] Such floods cause rivers to leave their banks and homes to go underwater.[38] Floods can be exacerbated by fires during the previous dry season, which cause soils which are sandy or composed of loam to become hydrophobic, or repellant of water.[39] There are various ways government organizations help their residents deal with wet season floods. Flood plain mapping is conducted, which helps diagnose what areas are more prone to flooding.[40] Instructions on how to control erosion through outreach is also done via telephone or the internet.[41]
Life adaptations
Humans
The wet season is the main period of vegetation growth within the savanna climate regime.[42] However, this also means that wet season is a time for food shortages before crops reach their full maturity.[43] This causes seasonal weight changes for people in developing countries, with a drop occurring during the wet season until the time of the first harvest, when weights rebound.[44] Malaria incidence increases during periods of high temperature and heavy rainfall.[45]
Animals
Cows calve, or give birth, at the beginning of the wet season.[46] The onset of the rainy season signals the departure of the Monarch butterfly from Mexico.[47] Tropical species of butterflies show larger dot markings on their wings to fend off possible predators and are more active during the wet season than the dry season.[48] Within the tropics and warmer areas of the subtropics, decreased salinity of near shore wetlands due to the rains causes an increase in crocodile nesting.[49] Other species, such as the arroyo toad, spawn within the couple months after the seasonal rains.[50] Armadillos and rattlesnakes seek higher ground.[51]
