Warmer weather sparks flooding fears
By Christin Nance Lazerus email@example.com February 19, 2014 10:30PM
Flood waters inundate a neighborhood off Calumet Ave. (top) in Dyer, Ind., Monday, September 15, 2008. Photo by Guy Rhodes for The Post-Tribune.
Updated: March 21, 2014 3:34PM
Name a type of weather — snow, freezing rain, sleet, hail, squall, and thunderstorms — and it likely will hit Northwest Indiana and the Chicago area over the next 24 hours. Combined with temperatures possibly reaching the mid-50s by Thursday afternoon, rapid snow melt could produce localized flooding, which communities are already working to prevent.
Heavy rain will start late Wednesday night, according to the National Weather Service, though Northwest Indiana should be east of the eye of the storm. Freezing rain and ice is possible around the same time, ending Thursday morning, particularly north of Interstate 80.
Temperatures reached the mid-40s on Tuesday and Wednesday, starting snow melt. As of 5 p.m. Wednesday, the Little Calumet River measured 6.65 feet — 12 feet is flood stage — and Hart Ditch reached 2.21 feet in Dyer and 0.99 feet in Munster, where the minor flood stage is 6 feet.
A flood watch will be in effect from 3 a.m. Thursday until 6 p.m.
Dan Repay, executive director of the Little Calumet River Basin Development Commission, said flooding most likely won’t occur on the river itself, but ice jams could pop up if the ice starts to break up during rapid snowmelt.
“Ice could built up under bridges, in culverts and elsewhere and cause flooding,” Repay said. “Mostly, sewers may be overwhelmed and streets could get flooded. It all depends on the intensity of the rain, if it’s an inch over 24 hours or an inch in one hour.”
The amount of snow on the ground as of Tuesday was estimated between 10 and 21 inches, which equates to 2 to 4 inches of rain.
Many public works departments spent time Wednesday making sure catch basins were cleared of snow and other debris.
Highland Assistant Public Works Director Bob Johnsen said about 19 public works and parks department employees were clearing catch basins, some with back loaders, and also hauling out snow that has accumulated in large mountains during the day on Wednesday. A crew of 15 public works employees will work on issues that arise overnight.
Warm air should enter the area around late morning, speeding up snow melt and possibly leading to fog. A squall may arrive in the afternoon, leading to damaging winds near 60 mph.
The National Weather Service said the frozen ground, which is estimated at one foot, is going to prevent much of the moisture from being absorbed, so most of any rain that falls will be runoff.
Repay said he went to Gary on Wednesday to see if there were any potential blockages and other issues, but it was difficult to find every issue due to significant snow still on the ground, particularly if beaver dams are obstructing any outflow pipes.
Gary Sanitary District Dan Vicari said melting snow enters the sewer system a little more slowly, so typically that keeps the wastewater treatment plant from being inundated and prevents possible sewer overflows.
Gary spokeswoman Chelsea Whittington said the city is reaching out to residents to alert them of possible flooding, telling them to keep an eye on basements and other possible flood-prone areas.