Heavy precipitation events can be measured by tracking their frequency, examining their return period (the chance that the event will be equaled or exceeded in a given year), or directly measuring the amount of precipitation in a certain period (for example, inches of rain falling in a 24-hour period). However, changes in the intensity of precipitation, when combined with changes in the interval between precipitation events, can also lead to changes in overall precipitation totals. Heavy precipitation does not necessarily mean the total amount of precipitation at a location has increased-just that precipitation is occurring in more intense events. 2 In addition, runoff from precipitation can impair water quality as pollutants deposited on land wash into water bodies. 1 The potential impacts of heavy precipitation include crop damage, soil erosion, and an increase in flood risk due to heavy rains (see the River Flooding indicator)-which in turn can lead to injuries, drownings, and other flooding-related effects on health.
When more moisture-laden air moves over land or converges into a storm system, it can produce more intense precipitation-for example, heavier rain and snow storms. Warmer oceans increase the amount of water that evaporates into the air. What constitutes a period of heavy precipitation varies according to location and season.Ĭlimate change can affect the intensity and frequency of precipitation. Heavy precipitation refers to instances during which the amount of rain or snow experienced in a location substantially exceeds what is normal. 4, 5 For more information on trends in overall precipitation levels, see the U.S.
Nine of the top 10 years for extreme one-day precipitation events have occurred since 1990 (see Figure 1). In recent years, a larger percentage of precipitation has come in the form of intense single-day events.The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. The cookie is used to store the user consent for the cookies in the category "Performance". This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other. The cookies is used to store the user consent for the cookies in the category "Necessary".
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