WISCONSIN - The Blood Center of Wisconsin says it's running dangerously low on blood supply.

The center likes to keep three to four days reserve but says it's down to only about a half day's supply of blood. 

So, why the shortage? The flu season has kept people from donating and a lot of donors decided to not come in during last week's snow storm.

"A loss of a portion or all of a days blood donations is very impactful when the supply is exceptionally low to begin with so we're on an emergency appeal asking donors to come and donate and help get that supply back up."

Anyone eligible to donate can make an appointment by calling 1-877-be-a-hero. Walk-ins are also welcome at the blood center.