Updated 02/18/14 – 10:54 a.m.
CHICAGO (CBS) — After nearly five inches of snow on Monday, Chicago residents were digging out again on Tuesday, and were running out of places to put all the snow. All that snow could create another problem when it begins melting, possibly causing flooding in some areas.
With almost more than a month of winter still to go, it already has been the fifth snowiest winter on record in Chicago, with 67.9 inches so far at O’Hare International Airport.
As 5 inches fell at O’Hare on Monday — and more than 6 inches fell in other parts of the city — Streets and Sanitation plows spent most of the day clearing the city’s main streets, and did not begin plowing and salting side streets until early Tuesday morning.
The full fleet of 287 snow plows salt spreaders, and 26 smaller four-wheel drive plows began clearing side streets around 1:30 a.m. on Tuesday.
With a thaw expected to begin Tuesday afternoon, and highs above freezing through Friday, city water crews have been clearing gutters and storm drains to help prevent flooding when the snow starts to melt.
“It’s very vital, because this is the main part of your waste water/rain water system; along the curb lines, you keep your gutter boxes and catch basins open,” said Water Department worker Dwight Nash.
City officials also were urging residents to help keep storm drains clear by clearing away ice and snow when they shovel their own sidewalks or clear off their cars.
The rate of melting water will depend on the temperature, moisture in the air, wind, and even the color of the snow. Clean white snow reflects light, and melts slower; while dirty black snow absorbs light, and melts faster.
With the ground frozen up to 12 to 16 inches deep, runoff from melting snow has nowhere to go but storm drains, and rivers and streams. In much of the Chicago area, 9 inches of snow or more already were on the ground before Monday’s winter storm, much of which could melt over the next few days. All that melting water could overwhelm storm drains, or swell rivers and streams to flood stage.
If storm drains are covered with ice or debris, melting snow could flood streets, and then refreeze overnight when temperatures drop below freezing again.
Despite three days of temperatures above freezing, don’t expect all the snow on the ground to melt. It typically takes three consecutive days of 50 degree temps to melt 4 inches of snow. Much of the Chicago area has 9 inches or more on the ground, and the mercury likely won’t reach higher than 45 degrees this week.