September 30, 2014

Severe storms a possibility for eastern Nebraska

Round one of rain moved through eastern Nebraska just before noon today as predicted. Now get ready for round two. National Weather Service – Valley Meteorologist Cathy Zapotocny says there is a stronger warm front to the south and that will have more dynamics including deep moisture and upper level support. While it is too early to predict the strength of storms and pin-point locations it is a good idea to be prepared.

Zapotocny says these storms could bring hail, heavy rain, strong wind and the possibility of a tornado.   She says Nebraskans are used to severe weather in May and June but we have a secondary peak in September but typically it is not as common.

There is a chance of lingering rain through Wednesday morning. You will need a light coat or sweater tomorrow. Temperatures will be about 20-degrees cooler than today.

Corps of Engineers offers more detail about rising Missouri River

This is what the Corps is hoping to avoid on the Missouri River.

This is what the Corps is hoping to avoid on the Missouri River.

Officials with the U.S. Army Corps of Engineers are now offering more details about how high the Missouri River will rise over the next few months.

Releases are being increased from the four lower dams on the Missouri following heavy rains in August in an effort to cut flood risks. Jody Farhat is chief of the Water Management Division in the Omaha office of the Corps.

“Our latest forecast indicates higher releases from the main stem reservoirs this fall in order to prepare the reservoir system for 2015, thus, reducing future flood risk potential,” Farhat says. “The higher releases will raise river levels along the lower river on average three to four feet above the level seen for most of the summer but will be well within the channel unless we experience a significant amount of rain.”

Farhat says they can cut back on those releases if there’s more heavy rain.

“If that should occur, releases may be reduced temporarily as part of our normal flood risk reduction measures and the reservoir system remains well positioned for this type of operation,” Farhat says. “We’ll continue to monitor the conditions across the basin as we move through fall and we’ll continue to make any necessary release adjustments.”

Farhat says releases from Gavins Point Dam near Yankton will be stepped up from the current release rate of 38,000 cubic feet per second to beyond 45,000 during the next several days and they’ll remain near that level throughout the fall.

“If you look back through our records, in about 25% of the years we’ve had releases above 40,000 in the fall,” she says. “It’s actually a very good time of year to evacuate flood water from the reservoir system. We do it routinely. We wait until the fall months and then we evacuate most of the water before the 1st of December.”

The excess water will also allow the Corps to extend the navigation season ten days and provide higher winter releases, which Farhat says will benefit winter hydropower generation and reduce risks to water intakes during periods of ice formation this winter.

By Jerry Oster, WNAX, Yankton


Missouri River levels are rising and will continue climbing

Gavins-Point-DamWith all the rain in recent weeks across the Midwest and Northern Plains, water levels are rising along the Missouri River basin — and the water will likely remain high through fall.

Dave Becker, operations manager for the U.S. Army Corps of Engineers at Gavins Point Dam, says they’re having to increase the releases from the dam near Yankton.

“Our runoff here above Sioux City has gone now up to 141% of normal, so the upper reservoirs are really storing quite a bit of water and we need to evacuate that this fall while we can,” Becker says. “Our flows are steadily being increased.” Becker says the high water levels will likely continue for a few months.

“Releases are expected to be up there through the fall, probably until about Thanksgiving,” he says. “They have extended the length of the navigation season which normally stops a little before Thanksgiving so they’ve extended that a little bit.”

Repair work is still underway on several of the spillway gates at Gavins Point Dam. Becker says they can use the spillway and continue the repairs.

“Right now, we’re using five gates and we may go up to as many as using eight gates for these releases,” he says. “Even though we have four gates being worked on, we have plenty of gates we can use to release the excess water.”

The river has risen about two feet at the gauge on the Meridian Bridge in Yankton, but it’s still well below flood stage. Releases from all the main stem dams are being increased to move the water before winter arrives.

By Jerry Oster, WNAX, Yankton



Study: Nebraska winters will still be snowy despite climate change

Snowplow3A national report on climate change finds even with global warming, we’ll still have plenty of snow in the winters ahead in Nebraska and across much of the country’s northern half.

Climatologist Harry Hillaker says climate change is very gradual and snow blowers and shovels will remain necessities. Hillaker says the report from the Massachusetts Institute of Technology didn’t exactly go out on a limb in predicting continued snowy winters for the Midwest.

“When you think about it, that’s not really much of a surprise, I guess the basic mechanism on how we get snow is not going to be changing in a warmer world,” Hillaker says. “The number of opportunities may be decreasing but the storms could be just as intense but probably not as frequent as what we’ve been seeing in years past.”

The Old Farmers’ Almanac forecasts the winter ahead will be colder than usual, then next summer will be hotter. The publication predicts winter temperatures, precipitation and snowfall will all be below normal, with the coldest period running from early December into the first half of January. Hillaker says it’s an extreme challenge to accurately predict the weather several months in advance.

“Certainly, not very easily and there’s lots of outfits out there like the Farmer’s Almanac and some private forecasters that attempt to do that sort of thing,” Hillaker says. “I don’t know if anyone’s attempted any kind of study of how accurate those prognostications are, but certainly it’s very, very difficult and we’ve got a long ways to go in those longer-range outlooks.”

While scientific advancements are making forecasts more on-target, Hillaker says no one can really predict now, at summer’s end, what the weather will be this winter.

“Certainly, the day-by-day forecasts, out a week or two, have gotten far, far better than they used to be just in the last 20 or 30 years, tremendous improvements,” Hillaker says. “On that longer range, say from 30 days on out, there’s some skill there, but still a lot of guess work.”

The MIT study predicts that some regions will see less snowfall, but the snowfall extremes may actually intensify.

No day off for Dakota City, recovering from severe storms

Nebraskans in extreme northeastern Nebraska are spending today not at cook-outs, but at clean ups.

Dakota City is recovering the Labor Day after severe thunderstorms with high winds touching 80-miles-per-hour at times took down power lines and did some structural damage throughout the city.

Dakota City Mayor Jerry Yecevich says all the destruction is still being assessed.

“We’re working on the infrastructure first; getting the streets cleared,” Yecevich tells Nebraska Radio Network affiliate WNAX. “We still do not have power back on in all the residents in town, yet. That’s a goal. We need to get that back up so we can get people in their homes. Last night we had some problems with gas leaks. Some of these trees were uprooted.”

The storm crossed the Missouri River and hit Sergeant Bluff, Iowa hard. It also blew over semis and blew debris onto I-29, which had to be closed for a couple of hours.

Yecevich says though the storm caused some structural damage in town, the biggest blow was to the power grid.

“A lot of it are trees; then with the downed power lines,” according to Yecevich. “There are some garages, some small buildings that got hit (by) trees, vehicles. There is some minor home damage. We haven’t been through everything yet to know exactly what all has been damage. We’re kind of early in the stages.”

Jerry Oster, WNAX, contributed to this article.