CHICAGO (CBS) — Early voting has begun for the upcoming runoff election for mayor and more than a dozen aldermanic races.

Polls are open for early voting from 9 a.m. to 5 p.m. Mondays through Saturdays through April 4 in all 50 wards; voters can cast their ballot at any of the locations, not just the one in their ward. Early voting also will be available on Sunday, March 29, from 9 a.m. to 3 p.m. at every location.

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If you have not registered to vote, you can register at any early voting location, but you must also cast your ballot at the same time.

The last day of early voting in Chicago is April 4. The runoff election will be held on April 7.

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Despite heavy snow Monday morning, approximately 1,000 votes were cast in the first hour of early voting, according to the Chicago Board of Election Commissioners. With the first mayoral runoff election in Chicago history, election officials said early voting might potentially set a record.

In addition to the runoff between Mayor Rahm Emanuel and challenger Jesus “Chuy” Garcia, at least 18 wards have runoffs in aldermanic races.

The 33rd Ward does not have an aldermanic runoff at this point, but Ald. Deb Mell got only 17 more votes than she needed to avoid a runoff, and challenger Tim Meegan has gone to court to force a recount, which could result in a runoff if a recount is granted and Mell falls short of the 50 percent plus one she needs to win outright.

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For a full list of all early voting locations in Chicago, click here. A list of all wards in which there is a runoff in the race for alderman is available here.