What is it?
Chinook winds are warm, dry winds that blow at intervals down the eastern slopes of the Rocky Mountains. Severe down slope winds are warm, dry air flows that travel from higher to lower elevations, exceeding 58 miles per hour.
What’s the Risk?
The Front Range cities of central Colorado are built along the foothills of the Rocky Mountains at elevations that average 5,000 feet or more. When down slope flow occurs, mountain air is transported down from the mountains into Fort Collins. This air is warmed and becomes relatively drier. In the winter, warm, dry down slope flow can turn a cold day to warm in a matter of minutes and melt several inches of snow in a few hours. When this happens we refer to the wind as a Chinook.
If the down slope flow develops in the winter, (when the winds at the mountain tops are much stronger) a low pressure trough often develops out on the Plains. When this happens, the down slope winds can become extremely strong. If the wind gusts exceed 58 mph, we refer to the event as a severe down slope wind.
How Should I Prepare?
To help protect your home during a severe wind or rain storm:
- Close and lock windows and doors so wind vibrations won't open them.
- Pull curtains and drapes over unprotected glass areas. This could prevent injury from flying glass if the window is broken.
- Check for loose objects that could be blown against the side of the house. Normally harmless objects can become destructive in hurricane-force winds. Put away bicycles, children's toys, lawn furniture, garbage cans and lids and other loose items. Tie down objects that can't be stored inside.