Rains, warm temps chip away at melt in Red River Valley, but will fuel surge
Rains and mild temperatures melted snow that now trickling into streams and rivers prompted forecasters to issue a flood watch Thursday for the southern end of the Red River Valley and predict the river in Fargo will surge 5 feet in the next week.
The National Weather Service in Grand Forks predicts that the Red River in Fargo-Moorhead, which was above 16 feet Thursday, will reach 21.8 feet in a week.
The season's first river forecast came as four days of rain expected to total about 1.25 inches in Fargo and much of the area were winding down.
The rain has totaled about .08 of an inch in Grand Forks.
Thursday's river forecast predicts the Red will reach 18.1 feet in Fargo-Moorhead about noon Monday, crossing the minor flood stage, which begins at 18 feet. Major flood stage begins at 30 feet.
In Wahpeton-Breckenridge, the Red was about 9.2 feet Thursday, less than a foot below the minor flood stage of 10 feet.
The Red River was at 17.6 feet at East Grand Forks on Thursday evening, far below minor flood stage of 28 feet, and the weather service didn't add a flood forecast for this end of the Valley. Major flood stage is 46 feet at East Grand Forks.
But melting has gone apace with the temperature remaining above freezing all night and rising into the high 30s during the day.
The results are visible.
The snow depth at the weather service's measuring site on UND's campus has fallen 6 inches the past week and was pegged at 9 inches Thursday.
So far this month, Grand Forks has received 0.85 of an inch of precipitation, mostly as rain and half of it in one day, Tuesday, according to the weather service.
Normal precipitation for the first 11 days of the month is only 0.32 of an inch.
Since Jan. 1, Grand Forks has received 2.11 inches of precipitation, 0.38 of an inch above the 30-year norm.
Temperatures next week will climb into the 40s beginning Sunday and it looks that way into at least Wednesday, the weather service said.
"How fast will that really get things going?" asked Dan Riddle, the weather service's lead forecaster in Grand Forks. "Will the true melt begin?"
Meanwhile, forecasters are watching another storm system that could bring moisture late next week. A cold snap is expected to follow, which should stall runoff for awhile.
"Next week will be kind of the key," Riddle said. "The snow on the ground is primed for melting."
Below-normal temperatures could linger for most of the rest of March, with highs in the 20s and lows in the teens to single digits.
That would mean the area would have to wait for another warm-up in early April to get the ice out of rivers, Riddle said.
Hydrologists caution that ice-covered rivers will cause levels to fluctuate, creating uncertainty in the exact timing and magnitude of increases.
Better river forecasts will be possible as snowmelt progresses, said Mike Lukes, a hydrologist for the weather service.
"Things are starting to trickle in," he said.
It's too soon to predict when the Red River will crest in Fargo-Moorhead, Lukes said. Current predictions, which extend two weeks, do not indicate a crest during that period.