Starting today, 7/20/18 and continuing through the weekend, the central and eastern states will experience multiple rounds of large storm complexes and lines of thunderstorms. These types of systems have the capability of extremely high rainfall rates which cause isolated flash flooding. In addition to the flooding concerns, there is also a slight risk of widespread wind damage.
This round of severe weather is due to an unusually sharp upper-level plunge of the jet stream by July standards carving into the Midwest and Southeast, punching over warm, humid air near the surface.
Flash Flood/Flood Safety Tips:
1. Nearly half of all fatalities in a flash flood involve a person driving a vehicle. Do not drive into a flooded area – Turn Around Don’t Drown! It takes only 2 feet of water to float away most cars. It’s amazing how powerful we feel when we get behind the wheel – don’t do it!
2. It takes only 6 inches of fast-moving water to sweep a person off their feet – don’t walk through a flooded area!
3. If you are camping in a river valley, move to higher ground if thunderstorms with heavy rains are in the area. Do not attempt to drive away.
4. Don’t operate electrical tools in flooded areas.
5. Most flash flood deaths occur in the middle of the night when it is more difficult to see rising water levels judge the depth of water covering road surfaces.
Severe Thunderstorm Straight-line Winds:
1. Don’t underestimate the power of strong thunderstorm winds known as straight-line winds – they can reach speeds of 100 to 150 mph. Hurricane-force winds start at 74 mph. Wisconsin does experience these kinds of winds!
2. If a severe thunderstorm warning contains hurricane-force wind speeds seek shelter immediately (as you would for a tornado situation).
3. Stay away from windows and go to the basement or interior room/hallway. Do not use electrical appliances.
4. Be aware that tall trees near a building can be uprooted by straight-line winds – that tree can come crashing through the roof of a home and crush a person to death.
5. Powerful straight-line winds can overturn a vehicle or even make a person air-borne when they get up over 100 mph!
6. One type of a straight-line wind event is a downburst, which is a small area of rapidly descending rain-cooled air and rain beneath a thunderstorm. A downburst can cause damage equivalent to a strong tornado!