MINNEAPOLIS--Blizzards and extreme cold in the Midwest caused several deaths and many emergencies yesterday, as temperatures in many areas dropped to their lowest this century.

The weather stranded travelers and left thousands without power in wind chills as low as 90 degrees below zero in Minnesota and several other states. Officials blamed at least three deaths on the unusually harsh weather.

Mayor Jane Byrne declared an emergency in Chicago, where the temperature fell to minus 76 with a wind-chill of minus 81. As many as 50,000 Chicagoans were without electricity as wires snapped in the extreme cold, a spokesman for Commonwealth Edison said yesterday.

The Chicago Building Department received close to 100 calls an hour from tenants without heat, a spokesman said.

Other Midwest communities reported blocked roads, downed power lines and abandoned cars.

The cold weather has pushed deep into the South and across the East. The National Weather Service yesterday predicted a hard freeze for most of Florida, including the citrus belt.

Power failures in the Maryland suburbs of Washington left 2000 customers of Potomac Electric Power Co. without power in six-degree weather.

Officials at City Hall in Philadelphia yesterday said the city received over 500 calls for emergency heat.

Dr. Kent Schwitzer, a Minnesota physician, warned that alcohol can be fatal in extreme cold and advised those who had consumed alcohol to remain in doors.

Alcohol not only impairs judgment but also dilates the external blood vessels of the skin, causing the body to lose heat more rapidly, Schwitzer said.