Summer rain stocks dams
- June 19, 2021
- Posted by: OptimizeIAS Team
- Category: DPN Topics
No Comments
Summer rain stocks dams
Subject : Geography
Context : Although the monsoon has not covered the whole country yet, summer cyclones and thunderstorms have left reservoirs with more water than their average at this stage.
Concept :
- The summer of 2021 saw unusually cool day temperatures over most regions. This could have led to below-average evaporation from surface water stocks across the core heat zones, where heatwaves and high day temperatures are common during March-June.
- The cooler summer was also due to frequent thunderstorms that brought rainfall spells at many places between March and May.
- During the second and third weeks of May, Cyclones Tauktae and Yaas caused widespread rainfall over two-thirds of the country.
- The all-India weekly rainfall during May 12-19 and May 20-26 was, respectively, 127% and 94% above the Long Period Average.
Long Period Average (LPA):
- It is the average rainfall recorded during the months from June to September, calculated during the 50-year period, and is kept as a benchmark while forecasting the quantitative rainfall for the monsoon season every year.
- IMD maintains an independent LPA for every homogeneous region of the country, which ranges from 71.6 cm to 143.83 cm.
Thunderstorms
- Thunderstorms and tornadoes are severe local storms. They are of short duration, occurring over a small area but are violent.
- Thunderstorm is a storm with thunder and lightning and typically also heavy rain or hail.
- Thunderstorms mostly occur on ground where the temperature is high. Thunderstorms are less frequent on water bodies due to low temperature.
Motion of a thunderstorm
- Path of a thunderstorm is erratic. Motion is primarily due to interactions of its updrafts and downdrafts.
- The speed of isolated storms is typically about 20 km (12 miles) per hour, but some storms move much faster.
- In extreme circumstances, a supercell storm may move 65 to 80 km (about 40 to 50 miles) per hour.
Downbursts
- Downdrafts are referred to as macrobursts or microbursts.
- Macroburst is more than 4 km in diameter and can produce winds as high as 60 metres per second, or 215 km per hour.
- A microburst is smaller in dimension but produces winds as high as 75 metres per second, or 270 km per hour
- They are seriously hazardous to aircrafts, especially during takeoffs and landings.