Updated 07/20/11 – 6:57 p.m.

CHICAGO (CBS) — Not since the blizzard in February has the Chicago Fire Department called so many extra paramedic crews into service.

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But as WBBM Newsradio 780’s Steve Miller reports, the city is calling out the extra paramedics from Wednesday through Sunday, because of the heat wave.

With high temperatures in the forecast that could reach or exceed 100 degrees Wednesday, Chicago Fire Department Media Affairs Director Larry Langford says the department wants make sure paramedics are ready to respond when they’re needed.

Initially, on Wednesday morning, Langford said that five extra ambulance crews — with two paramedics each — were being added to the streets to deal with the rising number of heat-related medical issues. By late Wednesday afternoon, the city had added a sixth extra ambulance crew.

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“They’ll be on the street Wednesday through Sunday to augment our regular force in anticipation of the high temperatures and possible spike in medical runs,” Langford said.

Langford says the ambulances will be “strategically placed throughout the city.” He says if it turns out the city does not need those extra ambulances, it can release them.

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He said the last time this many ambulances were called into service was for the blizzard on Feb. 2 and 3, which dumped 21.2 inches of snow on the area and has gone down as the third worst blizzard in Chicago history.