High Water – Memorial weekend weather increases snowpack, rains in forecast

Recent cool weather has dropped the level of rivers and streams around southwest Montana, but that’s not going to last long, according to a hydrologist with the National Weather Service in Great Falls.

The floods of 2011 haven’t really made much of an impact to Madison County, but it’s still early, said Gina Loss during a weekly web briefing with county, state and municipal officials from around southwestern and central Montana.

All over eastern Montana, floodwaters have damaged homes, property and crops and caused thousands of evacuations.

The outlook is still grim as the mountains all over Montana still hold on to their copious amounts of winter snow. As of Tuesday the snowpack in every river basin in the state, except one, exceed 200 percent of average, Loss said.

In mountains around southwest Montana, the mountain snowpack actually grew over the past few days as snowstorms brought more than a foot to some high-country locations.

“The snow is just not coming out of those mountains,” she said.

In the Madison River Basin the snowpack is 210 percent of normal and the Jefferson River Basin is 220 percent of normal. In some high-country locations there’s still nearly four-feet of moisture trapped within the snowpack. So though it seems like we’re moving toward summer, from a runoff standpoint spring has hardly started, Loss said.

The outlook for area rivers is that they will continue to remain high from the rain storms and snowmelt through the next week, she said.

“We do have a few storms that will go through over the next few days,” Loss said.

However, she doesn’t expect temperatures to warm enough to really accelerate runoff. The two-week outlook is for cooler than normal temperatures and wet conditions.

The Big Hole River near Melrose did hit flood stage last Thursday for about a 24-hour period. In recent days the river has dropped substantially, but that should change.

“We do expect that one to start turning in the next few days and start to rise and it looks like it could reach a moderate flood stage,” she said.

Officials are predicting the lower Big Hole will hit flood stage again Wednesday or Thursday. The Jefferson River near Twin Bridges could get close to flood stage during that time frame as well.


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