Flood season arrives with warm-up
It's beginning to look a lot like flood season.
"Watch your sump pumps," said Mike Gillispie, hydrologist for the National Weather Service in Sioux Falls. "There's going to be a lot of water starting to try to soak into the ground."
Gillispie said flooding is likely to begin occurring on both Firesteel Creek and the James River near Mitchell this weekend as snow across the region melts because of warmer temperatures. The severity of the flooding will depend on the amount of precipitation received in the coming weeks.
Monday, the James River near Mitchell had a depth of 12.4 feet, while Firesteel Creek had a depth of 3.7 feet.
Gillispie said the James is expected to hit its flood stage of 17 feet later this week and could be near 21 feet next Monday. The James' record crest near Mitchell is 25.46 feet, set one year ago this week.
Firesteel Creek is expected to crest at approximately 8.5 feet later this week, only slightly above the 8-foot flood stage. The Firesteel Creek observation station near Mount Vernon observed a record crest of 16.1 feet last July.
"It doesn't look terribly bad for Firesteel," Gillispie said.
Temperatures are expected to be in the 50s today and increase to the 60s on Wednesday, with more 50s and 60s after that. That's expected to melt some of the 3 to 5 inches of snow remaining in the area, Gillispie said.
There is plenty of moisture already in the soil, Gillispie said. Some frost remains in the ground, but much of the soil has already defrosted.
Temperatures are expected to drop near freezing throughout the evening hours of the week, Gillispie said, but it likely won't be enough to slow the melting.
"Even if it drops below freezing, it will only be for a few hours," Gillispie said. "That's probably not going to be enough."
The percent of saturation 20 inches into the soil has risen from 39 percent to 56 percent in the past two weeks in the Mitchell area. At 40 inches, the level has risen from 31 percent to 69 percent.
The area between the James River Basin and the Big Sioux River Basin has approximately 3 to 5 inches above-normal soil moisture.
"It's definitely the bull's-eye of saturation across eastern South Dakota," Gillispie said.
Gillispie said soil moisture levels are slightly lower than last year's at this time, but he believes there is more snow on the ground this year.
"If we get in a situation with a little extra moisture now plus normal precipitation for the next three or four weeks, we could be really kind of right back at those same levels (from) last spring," Gillispie said.
Last year, farms, homes and businesses were inundated with flooding through the spring and into the summer.
In Sioux Falls, officials are gearing up for what could be record spring flooding on the Big Sioux River. The city is bringing in construction equipment and materials to strengthen levees.
The Army Corps of Engineers said it might cancel the March surge of extra water meant to help the spawn of pallid sturgeon, an endangered species. The corps aid the two-day March pulse could be canceled if the river level is already high from spring runoff.
Monday, Davison County Emergency Management Director Jim Montgomery picked up 15,000 sandbags "just in case."
Montgomery said he's cautiously optimistic that flooding will be minimal in the Mitchell area, as long as additional precipitation stays to a minimum.
"I think we're better off than we were last year," Montgomery said. "Mother Nature's going to do what it wants to do."
Montgomery also said the warm temperatures expected to melt area snow will thaw out the sand pile at the Davison County Highway Shop, making the pile ready for sandbags.