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Lots of snow, but that’s normal for ND: Snow samples measure moisture, help assess flood risk

FNS Photo by John Stennes Paul Johnson, a U.S. Army Corps of Engineers employee, measures the depth of the snow on top of the ice on the Red River on Thursday between Grand Forks and East Grand Forks, Minn.

EAST GRAND FORKS, Minn. — Bill Odell carried an auger early Thursday morning out onto the Red River near East Grand Forks, though his intentions weren’t to drill a hole for ice fishing.

Odell and colleague Paul Johnson are traveling around Minnesota conducting ice and snow depth surveys for the U.S. Army Corps of Engineers.

The snow survey samples assist the corps’ water management team with determining how much water is contained within the region’s snowpack.

The data collected are shared with the National Weather Service and U.S. Geological Survey, who use the data to assess flooding risks.

Snow depths and water content information collected by Johnson and Odell fell within the normal ranges defined by the weather service.

The weather service also uses satellites to map snowpack depths, but sometimes the images may seem a little off.

“If something looks fishy, we’ll go out and take a sample,” Johnson said.

Thursday’s stop was a routine one and started with the pair drilling three holes in the ice just south of the Sorlie Bridge. Measurements indicate the ice depth there is around 2.5 feet.

“It’s more ice than we’ve seen up north,” Johnson said, adding that other locations were logging around 2 feet of ice. “It makes sense though. We’ve had a long winter.”

The men have already made stops along the Red River and a few of its tributaries to the north in addition to cities such as Duluth, Warroad and Roseau.

Snow depth

Once ice measurements were collected, they headed north of the bridge in search of a good area to take four snow depth samples.

“You want to avoid areas with a lot of snowmobile traffic,” Odell said.

An abundance of snowmobile tracks in the Red River State Recreation Area required the men to take samples from the untouched snow that remained drifted nears trees.

Drifting snow can pose a problem for taking accurate measurements, according to Johnson.

“If it’s drifting, your results won’t be quite as typical,” he said.

To collect the sample, Odell pushed a hollow metal tube into the snow until it hit the ground. The tube’s outside is marked with a ruler, allowing depth to be measured before Odell empties the tube into a plastic bag.

The average reading near the trees was 15.5 inches. Farther north in Warroad, the men said they recorded snow depths closer to 30 inches.

Both are in the normal range for their respective areas. The weather service said low-end normal snow depth ranges for the southern portions of North Dakota and Minnesota fall between 8 and 12 inches. To the north, the range increases to 24 to 36 inches.

Water equivalent

Measuring the snow’s depth is just one component of assessing flood risks.

The bags of snow were taken back to the pair’s truck, placed on a scale and weighed to determine the snow-water equivalent.

The average weight of the four bags was three ounces. An ounce of snow roughly becomes an inch of water on the ground, according to Johnson. That means about 3 inches of water was present in the sample area, though drifting snow could skew that result.

Water content for the Grand Forks area has been running between 1.5 and 2.5 inches with amounts increasing for sites to the north.

South of Grand Forks, the area’s overall water content is a little less than the long-term normals because of much colder and drier air masses that have moved through this season.

With their work in East Grand Forks done, Odell and Johnson headed to Crookston and then will continue their journey south toward Moorhead.

Eventually, they’ll return to their base in St. Paul with data from about 30 snow and 10 ice survey sites in northern Minnesota.

Brandi Jewett

Brandi Jewett is a reporter for the Grand Forks Herald with beats focusing on northwest Minnesota, unmanned aircraft systems and East Grand Forks city government. A native of Valley City, N.D., 26 years worth of winters haven't scared her out of the state yet. Follow her work at grandforksherald.com, on her blog at droningon.areavoices.com and on Twitter and Instagram: @brandijewett. Send tips and story ideas to bjewett@gfherald.com. 

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