During the late spring and summer in southern Colorado, the main weather hazards are flash flooding, tornadoes, and severe thunderstorms. In this guide, you will learn what each warning means and how to respond during severe weather. Watches and warnings are issued by the National Weather Service and relayed to the public.
Watch vs Warning
A watch means that weather conditions are favorable for a specific type of severe weather to develop. This is when you should prepare. The type of watch issued depends on the main hazard expected that day. These have a large span in time and span, usually lasting hours to days and covering many counties.
On a day when flash flooding is the main concern, a flash flood watch will be issued. If severe thunderstorms are expected with little to no tornado threat is likely, a severe thunderstorm watch will be issued. On a thunderstorm day where tornadoes are possible, a tornado watch will be issued.
A warning means that a weather threat is imminent or happening now. This is when you should take action. Warnings will have a shorter span in time and space, lasting minutes to hours and covering cities or singular counties.
Warnings will also compound on each other. One single storm can have a combination of a flash flood warning, tornado warning, or severe thunderstorm warning. Whatever threat is present will be warned, regardless of the type of watch.
Flash floods are notably dangerous as water is powerful. Flash flood warnings will be issued based on a threshold. Cities can withstand less water than open fields and wildfire burn scars can handle even less water before flooding. When the rain rate exceeds the threshold, a warning will be issued.
To take action during a flash flood, find shelter indoors and avoid creeks and rivers. If you are outside, get to higher ground and never drive through flooded roads.
The minimum threshold for a severe thunderstorm warning is wind gusts of 58 mph and/or hail of 1 inch in diameter. This can be radar detected or observed by a storm spotter.
Regardless of whether a storm is warned or not, lightning is very dangerous. Shelter in a car or building until 30 minutes past the last strike.
A tornado warning will be issued when strong rotation is detected on radar or if weather spotters observe a funnel or tornado.
To shelter during a tornado warning, find a sturdy building. Go to the lowest floor and most interior room. A good rule of thumb is to put as many walls between you and outside as possible.
If you are outside with no building in sight, lay on the ground or in a ditch. This will help prevent debris in the tornado from hitting you.