Courtney Lawrence

The American Red Cross is facing a 35% drop in the last month.

Red Cross doctor Courtney Lawrence says the supply was already suffering because of this year's intense flu season.

But last weekend's winter storm is making it more difficult for hospitals to resupply.

Lawrence says the Red Cross is in need of all blood types, but there are shortages of type A negative, type B negative in platelets.

People with blood type O positive or negative are also strongly encouraged to donate, as this blood group is most often used in emergencies.