Michigan just misses 1000-year rain, hits southeast Wisconsin

A large area of very heavy rain has flooded large sections of southeast Wisconsin. Here’s a look at some unbelievable rain amounts.

These rain amounts fell in just one day-yesterday. In fact most of the rain fell in less than 24 hours.

The heaviest rain between six inches and just over 12 inches fell yesterday, August 10, between Milwaukee, Waukesha and just north of Milwaukee.

Here’s a good visualization of where the heavy rain fell.

The heaviest reliable rainfall measurement tallied up to 12.62 inches at Pewaukee, west of Milwaukee.

There was an unofficial rain gauge measurement of 14.50 inches, but that has not been accepted as valid by the National Weather Service. It doesn’t mean that’s an incorrect measurement. It’s just not a verified rain gauge reporting the heavy amount. It’s an important report because it may be a new Wisconsin state rain record. The National Weather Service at Milwaukee says they are going to look at the rain gauge to see if it is sited properly. There are official guidelines on where a rain gauge can be located. One of the criteria is a rain gauge is supposed to be twice the distance away from the tallest object. If there is a 25 foot tall tree in a yard, the rain gauge has to be 50 feet away from the tree.

Wisconsin may get a new state record rainfall if the National Weather Service accepts the rain gauge as a good gauge. The National Weather Service tells us it may take weeks to months to be accepted.

The data on rainfall frequency in that part of Wisconsin says a 100-year rain is between six inches and seven inches in 24 hours. The 500-year rain is 8.4 inches. The 1000-year rain is 9.5 inches.

With rainfall totals up to one foot in a day yesterday, this could be considered a 1000-year rain.