Long-awaited warmer temperatures melt snowpack too quickly, cause flooding

A built-up snowpack, combined with subzero temperatures and followed quickly by spring-like weather, sent torrents of water running through creeks, canals and rivers last week.

The resulting deluge caused flooding in Park, Big Horn and Washakie counties and prompted the deployment of Wyoming National Guard troops and teams from the U.S. Army Corps of Engineers and Homeland Security.

The weather sent water into the crawlspaces and basements of several homes in western Park County, but “we were pretty fortunate” overall, said Park County Homeland Security Coordinator Mart Knapp.

Unlike those in Big Horn and Washakie counties, rivers and streams in Park County stayed within their banks and did not overflow with ice jams.

A homeowner east of Cody, a couple residents up the North Fork of the Shoshone River near Wapiti and several homeowners up the South Fork called for help with flooding — and Knapp’s sure there were others who had problems and just didn’t call.

“We had some water runoff that overtopped the canal off the Greybull Highway” east of Cody, said Park County Engineer Greg Meinecke. “We basically had a small river running down through (Park County Road) 3FK, Ross Road and Musser Road. There was considerable road damage and private property damage.”

Meinecke said Park County crews and Park County Homeland Security did what they could to minimize flooding and damage to private property.

“Homeland Security was with me, and they brought in sandbags, and a contractor brought sand,” he said.

The sandbags were piled to create a berm around the homes and shops in the area, he said. The South Fork area also was hard hit, particularly the upper South Fork, Meinecke said.

“The worst of it is probably flooding in Diamond Basin and around Panorama Drive, about 13 miles out on the South Fork,” he said. “What we had up there was just simply a lot of runoff coming off BLM, state and private ground, and it all headed for low areas through natural waterways.

“That was a real bad one, and there was not a lot we could do to help on that. It was a lot more than what that area can handle.”

Homeland Security helped in that area as well, Meinecke said.

In addition, “we’ve got a lot of water damage all over Stage Coach Trail by the (Buffalo Bill) Reservoir,” he said.

In that case, “a big snowball broke loose up high. It gained snow and traction as it fell, and it came down on Stagecoach and blocked half that road,” he said.

Meinecke said the situation in Park County was very unusual.

Meinecke said, “What we had was a super-intense snowpack that had been deposited all this late winter, and in a matter of a couple of days, we went from 12 below zero to 55 degrees. So the ground was a little froze up, and where it wasn’t, it was super-saturated.

“When it turned hot like that, it just started to run off. It was a lot more runoff in places than we’ve seen in a long time.

“We try the best we can to plan our drainage ways and our culverts to handle at least a 1-in-25-years event,” Meinecke said. But that planning is for a cloudburst rainstorm scenario.

For county workers who had been plowing snow nearly continuously for days and weeks before, the weekend flooding was one more crisis the exhausted workers had to deal with.

But, “when the ground gets so saturated, it’s pretty hard to get heavy equipment on it,” Meinecke said. “You just make a big mess and get stuff stuck.”

On Monday, everything was beginning to dry out.

“Now we’re starting to really be able to put guys to work,” he said.

More precipitation — both rain and snow — was in the forecast for Monday night and today (Tuesday), but Knapp doesn’t expect a repeat of last week’s flooding.

“We’d have to get a tremendous amount of rain for that to happen again,” he said. “We’re going to watch it, needless to say, because the ground is pretty well saturated, but I just don’t think we’re going to see that right now.”

Other areas continued to deal with flooding on Monday.

National Guard members stacked up sandbags in Manderson and Greybull over the weekend and were continuing to do so on Monday. More flooding is expected there as warm weather melts ice jams in the river.

Kelly Ruiz, a spokeswoman for the Wyoming Office of Homeland Security, says seven homes were damaged in Greybull over the weekend but the extent of damage to those properties wasn’t immediately clear.