Flooding outlook favorable for Red River Valley
FARGO -- Abnormally wet weather so far this fall may have some Fargo-Moorhead residents worried that Mother Nature is planning another big spring flood.
But the National Weather Service says the outlook is favorable for less precipitation in the long term.
"At least at this juncture, you're in a lot better shape down there than you were in the previous fall," said Mark Ewens, data manager at the weather service office in Grand Forks, N.D.
Fargo Mayor Dennis Walaker said the city already received a call from one resident concerned about the wet fall, wondering what's being done to protect the city from flooding next spring.
"My view on all of this is not to worry about something that hasn't happened yet," he said.
Ewens said he understands the anxiety, given Fargo-Moorhead's record Red River flood last spring. Following the historic 1997 flood in Grand Forks, residents there raised similar concerns after heavy snowfalls, he said.
"But this is a totally different fall so far than we saw a year ago," he said.
Fargo received nearly 4.8 inches of rain from Sept. 1 to Wednesday - 2.1 inches above normal but below the 6.1 inches that fell during the same period last year.
A weak El Nino in the Pacific Ocean is expected to bring above-normal precipitation this fall, but not as much as what last fall's La Nina conditions produced, Ewens said.
October 2008 was the fifth-wettest October on record, with 4.46 inches of precipitation. And the 10.67 inches recorded at Fargo's Hector International Airport from Sept. 1 to Nov. 30 made it a record wet fall.
Conditions were drier this past summer than in summer 2008 in the Red River basin, Ewens said.
"So, there's a lot less moisture in the river systems to begin with," he said.
The long-range outlook calls for El Nino conditions to bring a drier winter overall with less snowfall than last year, Ewens said.
"And temperatures will be a little milder, so the overall conditions suggest that the ground wouldn't be as frozen nearly as deeply or as hard as it was last year," he said.
This fall's first "hard freeze" - defined as when the mercury dips below 28 degrees - was expected Thursday night or early today. The average date for the first hard freeze from 1971 to 2000 was Oct. 6.
A hard freeze doesn't mean the ground will freeze and trap all of its current moisture, Ewens said, adding that it takes continuous days and nights of below-freezing temperatures to make that happen.
"That was kind of the perfect storm of events last year where we had the heavy rains, so the ground was saturated to a much deeper level, and then when it started to get cold, it was consistently cold," he said.
The weather service predicted a 40 percent chance of snow tonight for Fargo-Moorhead, with accumulation of less than an inch possible.
The average date for the first inch of snow from 1940 to 2004 was Nov. 15. But measurable snow is not at all uncommon in early October, Ewens said.