Thursday, April 19th is the fifth day of Severe Weather Awareness Week for the state of Colorado, which continues through Saturday, April 22nd.

The topic for today is Downburst Winds and Hail!

Strong straight-line winds and large hail are major weather threats in Colorado.

Severe storms in Colorado include heavy rain, thunderstorms, tornadoes, straight line winds, hail, flooding, and lightning.
Tornadoes are often the headline story, but damaging straight line winds and large hail can also injure and kill animals and humans.

Straight line winds are caused by an area of air within a storm which is quickly cooled by precipitation, or by the evaporation of precipitation. This area of cooled air, which is heavier than the surrounding air, accelerates downward. As the cool air slams into the ground, it spreads out from the area of impact. This process, in extreme cases, can result in wind speeds exceeding 100 mph. Weather forecasters call these winds microbursts if they are less than 2 ½ miles across and macrobursts if they are greater than 2 ½ miles across.

These downbursts of cool air can be very dangerous for aircraft, and can cause extensive damage, injuries, and deaths at ground level. Take shelter indoors during wind storms. Anything that is not secured can quickly become airborne, causing damage and injury.

Hail also occurs often in Colorado. Hail forms within storms as liquid water freezes in the cold mid and upper levels of the storms. The hailstones are kept aloft by strong updraft winds for a time, and then cascade to the ground. In Colorado, hailstones vary from pea size, around 3/8 of an inch in diameter, to softball size, around 4 ½ inches in diameter.

Hailstones can do tremendous damage to crops, either as large hailstones, or as a large volume of small hailstones that accumulate to a depth of several inches. Large hail damages vehicles and buildings, and can be life threatening to animals and people.

The National Weather Service issues severe thunderstorm warnings for winds of 58 mph or higher or for large hail one inch in diameter or larger. When you hear of a severe thunderstorm warning, move to shelter as quickly as possible.

A NOAA All-Hazards Weather Radio is a great way to stay informed and receive severe weather watches and warnings.
Stay informed and know what to do when severe weather strikes. Visit for more information.

One thought on “Thursday, April 19th is the fifth day of Severe Weather Awareness Week for the s…

Comments are closed.