A streak of dry weather in the southern Red River Valley has given the region some "breathing room" when it comes to the threat of a fourth consecutive year of major spring flooding in 2012, the National Weather Service said today.
The weather service issued an assessment in early August outlining several "warning flags," including saturated soil and continued above-normal precipitation that put the valley on course for possible major flooding next spring.
An updated assessment released today said the relative dry weather since August has "slightly" improved some of the factors of spring flooding in eastern North Dakota and northwestern Minnesota.
But Mark Ewens, senior hydrometeorologist technician, said it wouldn't take much to bring the valley back to the situation it was in just a couple of months ago.
"The threat is still certainly there," he said. "What happens if in a week we have an inch or two of rain? Then we're back to where we were in August."
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Dry weather
The latest assessment shows wet soil conditions still persist in parts of the Red River Valley, along the Sheyenne River and in the Devils Lake Basin.
And climate records for the year back up the fact that 2011 has been wetter than normal for much of the region -- a problem, officials caution, because it increases the odds that the ground will be saturated at fall freeze-up.
That leaves little room for the soil to absorb runoff during the spring thaw, which means melting snow would immediately flow into rivers.
As of Oct. 1, Grand Forks had recorded 19.64 inches of precipitation in 2011 -- a total that's not far from the normal amount for the entire year of 21.52 inches.
The same is true in Fargo, which had 22.39 inches of precipitation by Oct. 1. That's less than a half inch from the normal amount for the year of 22.69 inches.
But Ewens said things have improved in recent months, especially in the southern valley. Fargo recorded just 0.23 inches of rain in September -- nearly 2.5 inches below the normal amount for the month, making it the fourth driest September since 1881 for the city.
The same was not true in the northern valley. Grand Forks had 2.57 inches of rain last month, which is more than a half inch above normal.
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Ewens said the recent dry streak has only benefited a "relatively small area" when compared to the entire Red River Valley. Still, the break from heavy rain has happened in a "critical" area -- the headwaters of the north-flowing Red River.
"It's dried out down south, and they've gained some storage in the topsoil which is always good news," he said. "It helps the potential for whatever we get over the course before freeze-up."
Waiting to see
Even with the drier weather, Ewens said river flows are still above normal for this time of year -- an outcome of the wet streak that has more or less affected North Dakota and Minnesota since 1993.
He said today's updated assessment shows some improved conditions that could have an impact on whatever flood threat the valley will face next spring.
"We have breathing room in the soil and in the system that we didn't have then," he said.
Still, Ewens said residents and officials shouldn't get "a false sense of security" from the slight improvements over the past two months.
A La Nina system re-emerged in the Pacific Ocean this year, making for a rare back-to-back occurrence of the system that typically means less than normal precipitation in the early fall but snowier, colder winters.
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Ewens said the latest climate outlook calls for above normal rainfall at the end of the month. The recent dry streak would allow the valley to easily handle another half inch or so of rain before freeze-up, but he said a couple of inches could bring the region back to the saturated state it was in earlier this year.
Still, the severity of spring flooding in 2012 is largely up in the air, he said.
The most significant factors of Red River Valley flooding are the rate of snow melt in the spring, amount of snow over the winter and any heavy snow or rain right as the rivers begin to rise.
"We want people to understand the conditions have gotten better, but we're not in a drought," Ewens said. "We've got to make it through the rest of this fall and winter season and see what's going to happen."
Reach Johnson at (701) 780-1105; (800) 477-6572, ext. 105; or send email to rjohnson@gfherald.com .
