Home » Uncategorized » Great Lakes water levels: How much will all this snow raise Lake Michigan, Huron?

Great Lakes water levels: How much will all this snow raise Lake Michigan, Huron?

Great Lakes water levels: How much will all this snow raise Lake Michigan, Huron?

By Mark Torregrossa | For MLive.com 
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on February 19, 2014 at 2:22 PM, updated February 19, 2014 at 5:28 PM 

lower-michigan-swe-final.jpg
This graphic shows how much water is currently contained in the snow on the ground. Most of Lower Michigan has several inches of water in the snow. (National Snow Analysis – NOAA)

There is obviously a lot of snow on the ground in Michigan, so how much will it help raise water levels in Lake Michigan and Lake Huron when it melts?

I asked the geography department at Northern Illinois University (my alma mater) to help me do some math.

The above graphic shows the “snow water equivalent” of all the snow on the ground currently.

Wei Luo, presidential research professor at NIU, imported the data from February 14, 2014 into a Geographic Information Systems (GIS) program.

Luo found that the drainage basin of Lake Michigan and Lake Huron held an average of 5.5 inches of water. So we took the area of Lake Michigan-Huron and put that amount of water on top of the lake surface.

The 5.5 inches of water on the drainage basin equals 11.1 inches of water on the lake. In other words, if all of the snow melted and made it into Lake Michigan-Huron, the lake level would rise 11.1 inches.

Of course, it won’t all make it into the lakes, notes Drew Gronewold, physical scientist at NOAA’s Great Lakes Environmental Research Laboratory.

The snow cover will also evaporate, sublimate, and even go into the deeper ground water, Gronewold said.

He does say that there are a lot of reasons to believe in a significant rise in lake levels of Lake Michigan-Huron this spring and summer. Aside from the snow-melt runoff into the lakes, the colder water now could mean lower evaporation this summer.

GLERL runs a computer model that attempts to predict lake levels. The research computer model currently predicts a nearly 17 inch rise on Lake Michigan-Huron. This level would be reached in July or August.

Lake Michigan-Huron has risen 15 inches since the low water mark in January 2013.

The U.S. Army Corps of Engineers, Detroit District, issues the official lake level forecast.

The most current forecast calls for Lake Michigan-Huron to rise 13.5 inches from the current level, said Jim Lewis, hydraulic engineer at the Army Corps of Engineers.

That means Lake Michigan-Huron will make gains on approaching its long term average.

When the lake level tops out this summer, Lake Michigan-Huron is projected to be only 11 inches below the long term average. Last year the lakes topped out 14 inches below long term average.

At the forecast peak level this coming summer, Lake Michigan-Huron will be eight inches higher than last summer.

Lewis also says Lake Michigan-Huron has risen 15 inches since the low water mark in January 2013. To put it in perspective, that is an additional 12 trillion gallons in Lake Michigan-Huron.

The current lake level forecast uses the Climate Prediction Center‘s summer forecast, and assumes near normal precipitation in spring and summer. If we should get into heavy rainfall like last spring, lake levels would be higher than currently predicted.

A new lake level forecast will be issued by the Army Corps of Engineers in March.

But it is safe to assume there will be more water to swim in this year. It just may be that the water may be a little too cold to stay in long.


Mark Torregrossa has been chief meteorologist for three TV news stations in Michigan. A resident of the state for 20 years, he has also gardened since age 10 and is an avid hunter. Email him at mark@farmerweather.com and find him on Facebook at facebook.com/mark.torregrossa and Twitter@weathermanmark

 

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