Ideal melt conditions allay flood fears in Lake County
The outlook of officials who deal with flooding in Lake County has improved markedly the past week as the heavy snow cover gradually has all but disappeared.
Rain and frozen ground would create issues in the weeks ahead, but the forecast the next week looks calm as the weather — for a change — has been a friend rather than a foe.
“The bottom line is that, so far, in terms of the melt, Mother Nature has been very kind to us,” said Kent McKenzie, Lake County's emergency management coordinator. “Someone said we have had near-perfect melt conditions.”
The snow piles began to disappear with mild temperatures during the day, while below-freezing temperatures at night halted the process but allowed runoff to be carried away.
Settling ponds, detention areas and low areas are full, and there is more water coming into the Chain 'O Lakes than going out. But there is no immediate threat of flooding, officials say, and the weather looks favorable until Friday.
“So far, we've been able to melt off a lot of our snow pack without causing major floods,” McKenzie said. “It doesn't mean we're out of the woods by any means.”
The Des Plaines River reading at Lincolnshire was 10 feet 6 inches on Friday morning. Minor flooding there starts at 12 feet 5 inches, and the crest is 16 feet 3 inches, according to McKenzie. At Des Plaines, the reading Friday was 2 feet 6 inches, with the record crest at nearly 11 feet.
The gauge on the Fox River at New Munster, Wis., on Friday morning was at 10 feet 2 inches. Minor flooding occurs at 10 feet.
“Unless we get an awful lot of rain, we could be in a good position,” said Ron Barker, executive director of the Fox Waterway Agency.
The Illinois Department of Natural Resources has restricted the flow of the Fox River at the Stratton Dam near McHenry and is using the Chain 'O Lakes as storage, said Rita Lee, a hydraulic engineer for the agency. The agency every winter drops the lakes level by 18 inches to make room for snow melt.
“I'm hoping that the Chain 'O Lakes will crest this weekend, and I anticipate the flow will remain high on the Fox River as we try to regain some storage that we've lost. That's because the ground is so frozen,” she said.
About 70 local officials from throughout the county attended two “pre-flood coordination briefings” hosted by McKenzie this past week. They were prompted by the National Weather Service forecast of a higher-than-normal probability of significant spring flooding for northern Illinois and southern Wisconsin.
That forecast still holds, said Kurt Woolford, chief engineer of the Lake County Stormwater Management Agency.
“Right now the conditions are primed if we get a large rainfall. A lot of saturated soils and frozen ground. You'll have instantaneous runoff,” Woolford said.
McKenzie said the frost depth is 36 inches, compared to the typical 18 to 24 inches.
“In the next week, things look great. It's anybody's guess what happens beyond that,” he said. “All of our rivers and streams and ponds are still full, and it will take awhile to get down.”