2011 flooding in western Iowa.

The National Weather Service is changing how it measures the depths of Iowa’s waterways, which also means a change in how much water will be needed to prompt the issuing of flood warnings.

Senior hydrologist, Jeff Zogg, says they’re shifting 44 of the 47 river forecast points across the state’s midsection.

“The reason we’re changing the flood stages and the flood categories across central Iowa is to give our flood warnings more meaning,” Zogg says. “We want to be sure that when we issue a river flood warning for a given location, that it actually means that something is going to occur.”

The National Weather Service office in Johnston serves 51 counties in central Iowa. He says the changes will impact about 30 rivers and streams across that area. “Over the years, due to mitigation activities, locations that may have been affected at a given stage are no longer impacted,” Zogg says.

“That requires us to raise the flood stage and the flood categories.” Almost all of the changes in river forecasting markers are being moved upward, meaning, a warning won’t be issued now until floodwaters reach a higher point.

“Many people have probably become used to us issuing river flood warnings for levels that don’t have much impact,” Zogg says. “Going forward, the flood warnings we do issue will definitely have more impact. They’re keyed in to impacts to life and property in the locations we do flood warnings for, so, they definitely need to pay attention to these flood warnings.”

Zogg anticipates the changes will mean a 50% reduction in the number of flood warnings the office issues this next year, versus previous years. The National Weather Service is scheduled to release its annual flood forecast for Iowa next Thursday, February 16th.

Learn more about the changes at “www.weather.gov/dmx“.

“This is the latest in the season we’ve gone without Des Moines hitting zero degrees or lower,” Deitsch said. The old record for the latest day to reach zero or below was set in 1914, when Des Moines reached two-below-zero on February 6. Des Moines has received 14.7 inches of snow this winter, well below the normal amount of 22 inches for this point in the season.

“Typically to get real cold temperatures, you need a pretty good snow pack on the ground,” Deitsch said. “And since we haven’t had that for much of this winter, temperatures have been a bit warmer than usual.”

Last year at this time, Des Moines had received 31.5 inches of snow, more than twice as much as this year. Deitsch said temperatures could dip below zero in Des Moines this weekend.

“Right now, we have low temperatures (forecast) in the single digits for those days. If we’re able to get rid of some clouds overnight, we could creep below zero on either Friday or Saturday. So, that’s something to watch,” Deitsch said.

In Des Moines, the temperature climbed into the 60s on three days in January. The only other time that happened was in 2002. The National Weather service reports, in terms of average temperature, this has been the 3rd warmest winter ever recorded in Des Moines.

It’s the 8th warmest for Waterloo, 5th for Mason City and 6th warmest winter – thus far – in Ottumwa.

Average temperatures (Dec 1 – Jan 31)
DES MOINES
1. 1918-19 32.0 degrees
2. 1914-15 31.8 degrees
3. 2011-12 31.7 degrees

WATERLOO
1. 2001-02 30.1 degrees
2. 1913-14 28.6 degrees
3. 1931-32 27.9 degrees
4. 1918-19 27.9 degrees
5. 1943-44 27.1 degrees
6. 1907-08 27.1 degrees
7. 1982-83 27.0 degrees
8. 2011-12 26.8 degrees

MASON CITY
1. 1913-14 27.3 degrees
2. 2001-02 26.6 degrees
3. 1943-44 25.6 degrees
4. 1905-06 24.6 degrees
5. 2011-12 24.4 degrees

OTTUMWA
1. 1931-32 33.4 degrees
2. 2001-02 32.5 degrees
3. 1988-89 32.2 degrees
4. 1946-47 31.4 degrees
5. 1938-39 31.4 degrees
6. 2011-12 31.2 degrees

National Weather Service meteorologist Frank Boksa says the storm will start with rain and change over to snow after midnight.

“We’re not looking for any big snowfall totals during the overnight hours – perhaps half-an-inch in the Des Moines metro.

Certainly, areas out west will change over first and they will see a little bit more snow by daybreak. We’re looking at two or three inches in western Iowa,” Boksa said. But, the heaviest snow is expected through the morning and early afternoon. Boksa said it’s difficult to forecast final snowfall totals because the snow will be so wet and heavy.

“Wet, heavy snow compacts more…this is a very difficult storm to try and pinpoint where the heaviest snow is going to be,” Boksa said. Some blowing and drifting of snow is possible tomorrow as northeast winds are expected between 15 and 30 miles an hour.

High temperatures across the state through the weekend will mostly be in the 30s.

Sundown spokesman Mark Dietz says mild conditions are better for beginners. “It’s a lot nicer to learn instead of when it’s zero and the wind’s blowing,” Dietz says. “The warm weather has its plus side, that being, it is more comfortable than what we could normally have here, which is much, much colder than this.”

Just across the Mississippi River in Galena, Illinois, Stuart Stoffregen is the marketing director at Chestnut Mountain. Stoffregen says it would take temperatures in the 50s and 60s for a couple of weeks before they would have to shut down.

“Being in the Midwest, you have to rely on technology and our snow-making is very top notch,” Stoffregen. “When it was colder a couple of weeks ago, we made piles and piles of snow. We have well over 50-some inches on the hill. Right now, the snow is a little bit softer but it’s still great for skiing and snowboarding.”

Iowa normally sees 60-degree days in January once in a decade. Last month, many cities hit 60 on four separate days, with some reaching 70. Still, forecasters say the cold weather is returning with the chance of snow on Friday night and Saturday.

He says there’s always a big contrast in snowfall across the state. “Some parts of northeast Iowa were quite a bit above normal, Guttenberg for example had 17.5 inches of snow for the month, which would be about double the usual amount there. On the other side of the spectrum…Logan in western Iowa had only six-tenths of an inch of snow for the month,” Hillaker says.

One thing that is much different from recent years is the amount of time the snow has hung around. Hillaker says rain and warm conditions melted the snow we got so the ground didn’t remain white very long after the snowfall, like it has in recent years.

“Especially the winter two years ago, 2009 and 2010, where some places such as Des Moines just obliterated the old record as far as duration of snow cover. So it’s a huge contrast from what we’ve seen in recent winters,” Hillaker says. “But again, not historically at the top as far as a lack of snow, but certainly less than usual.”

Part of the melting of the snowcover was due to warmer temperatures. Hillaker says the temperatures averaged about six degrees above normal for the month. “Actually not high enough to get in the top ten as far as warmest Januarys, but we certainly did have some very mild days mixed in there,” Hillaker says.

“Temperatures were into the 60′s on several different dates during the month in parts of the state, which is certainly not an everyday occurrence by any means in Iowa.” Hillaker says the overall precipitation for January was 63-hundredths of an inch, which is about two-thirds the normal average for the month.

“And with this warm weather, it’s melted quite quickly,” Dodd said. “We really aren’t recommending folks get out on the ice. We’ve already had one incident in Madison County. We know it’s tempting to get out there, but we recommend people stay off at this point.”

Authorities say 64-year-old Linda Jones and her friend, 80-year-old George Pierce, drowned Monday while ice fishing on a farm pond in Madison County. Dodd said many ponds and lakes had good ice as recently as Saturday, but Monday’s temperatures in the mid 60′s forced the D.N.R. to cancel some trout stocking and ice fishing events scheduled for this coming weekend in central Iowa.

“The ice was just not thick enough for doing that this year,” Dodd said. Ice fishing conditions are slightly better north of Highway 20, but Dodd said anglers are encouraged to use caution even in northern Iowa.

By Pat Powers, KQWC, Webster City

Des Moines had 65 degrees, beating the old record of 57. Ottumwa reached 65, breaking the old record of 59. Lamoni saw 63 degrees, knocking off the old record by three degrees. Webster City reached a high of 59, breaking the old record of 53 set in 1931.

Small says today’s temperatures will be above normal for this final day of January, but likely won’t see any new records set. There’s the possibility of snow by Friday.

By Pat Powers, KQWC, Webster City

“We’re forecasting totals of four to seven inches across northern, northeastern and eastern Iowa with lower amounts further south,” Lee says. Several northern Iowa school districts cancelled classes today due to the looming storm. The snow should last much of the day and

Lee says by the time it stops, it’ll be bitter cold.

Temperatures will fall overnight with clearing skies as the snow cover helps to make things even colder, with regular air temps dipping perhaps as low as 15-below zero. While Saturday should be mostly clear and cold, Lee says there’s a chance for still-more snow during the second half of the weekend.

It may be warm enough for some rain during the day on Sunday, rain that may change over to snow on Sunday night. For Iowans who are traveling today, road conditions are becoming hazarous in many areas. Check first by calling the state D.O.T.’s information line at 5-1-1.

By Pat Powers, KQWC, Webster City

“We have fairly modest-to-brisk northwest breezes and very cold temperatures combining for wind chills of 20 to 30-below across northern Iowa,” Lee says. More snow is on the way, too. Lee says several Winter Storm Warnings, Watches and Advisories will be going into effect soon for much of Iowa’s northern half.

“We’re expecting to see snow spreading in from northwestern Iowa after midnight tonight, continuing through Friday,” Lee says. “Accumulations across parts of northern Iowa will be close to five to seven inches, down around the Missouri border, virtually none, so there’ll be a pretty sharp gradient somewhere across central Iowa.” More super-cold air will be arriving in Iowa this weekend with another chance of snow by Sunday.

By Pat Powers, KQWC, Webster City

“Especially if you’re a semi truck driver pulling an unloaded trailer,” Gray-Fisher said. “Maybe you need to just pull off (the road) for a while and wait for the winds to subside. We had several semi tractor trailers jackknifing this morning and one actually flipped from the high winds.”

Most of the semi crashes happened on Interstate 80 between Des Moines and Iowa City. Snow totals across the state are being reported in the 1 to 3 inch range. “There hasn’t been a lot of snow, but the wind does present some problems. People are getting blown over outside of their traffic lane,” Gray-Fisher said.

In addition, some roads are slick from “wheel track glazing” as the wind blows snow across the road and it becomes icy from heavy traffic.

Motorists can check Iowa road conditions online at www.511ia.org or by calling 5-1-1. Clear, but blustery and cold conditions are expected overnight with lows near zero in the northeast to lower teens in southern Iowa. It should be sunny, but continued windy Wednesday with highs in the mid 20s and 30s.