Rain may help flood outlook but more warm temperatures needed, hydrologist says
FARGO - Rain usually exacerbates flooding, but this week's record rainfall may slightly improve the outlook for spring flooding, a National Weather Service hydrologist said Tuesday.
"Actually, the rain and the warm temperatures helped melt that snowpack and start moving the water to the rivers a little bit," said Mike Lukes at the Grand Forks, N.D., office.
The runoff was evident in the Red River at Fargo, which rose 3 inches from Sunday to Tuesday afternoon - a sizable jump. Lukes said the Red River level jumped about 3 to 4 inches from Fargo to Oslo, Minn.
On the downside, more water collected in ditches that won't become unplugged until the spring thaw, he said.
Fargo received a record 0.26 inch of precipitation Monday, breaking the record of 0.24 inch set on Feb. 9, 1894, the weather service said.
On Tuesday, the city broke another record with .32 inch of rainfall by 7 p.m. The previous record of 0.24 inch was set in 1886.
Lukes said rain falling on snowpack turns it into what's referred to as a slushier "ripe" snowpack.
"It'll help a little bit because it's getting more toward that point where a little bit of heat will turn it into water," he said.
Lukes said the best flood forecast is still the long-range spring flood outlook released Jan. 22, which forecasts a more than 90 percent chance of major flooding on the Red River at Fargo by April 30.
The next flood outlook comes out Feb. 27, he said.
Fargo street crews worked around the clock Monday and Tuesday to remove snow and ice from storm sewer drains, said Al Weigel, the city's public works operations manager. Some crews used steamers to melt the ice.
Weigel said there was a rush to get the water off the streets before it froze.
"The storm sewer can handle it," he said. "We just can't get it to the storm sewer is the problem."
In addition to the rainfall, Fargo set a record Monday for the date's highest minimum temperature. The low of 34 degrees broke the previous record of 30 degrees set on Feb. 9, 1976.
Lukes said spring flooding will depend heavily on the temperature and precipitation over the next several weeks, as well as the speed of the spring thaw and how much rain and snow falls during it.
"Maybe (the rain) helped a little bit, but again, we're going to have to get a lot more heat, a lot more warm days to really start getting that water moving into the river and get rid of the river ice," he said.