America’s blood supply has fallen to critically low levels in the wake of hurricanes and summer travel season.

The American Red Cross said the national blood supply has dropped nearly 25% since August, potentially threatening medical care for patients with an emergency need for blood, or those living with conditions such as cancer of sickle cell disease who depend on blood transfusions.

Hurricane Idalia’s impact on the southeastern U.S. caused more than 700 units of blood and platelets to go uncollected, the Red Cross said. Then, in August, donor turnout dropped due to travel and back-to-school activities, contributing to a 30,000 donation shortfall in that month alone. The Red Cross is also monitoring Hurricane Lee and its potential impact on the northeast later this week which could exacerbate the issue.

“For so many patients living with urgent medical care needs, crises don’t stop with natural disasters,” said Dr. Pampee Young, chief medical officer for the American Red Cross. “In fact, in some instances, the stress of a disaster can lead to a medical crisis for some individuals battling sickle cell disease. The need for blood is constant. Every two seconds, someone in the U.S. needs blood—an often invisible emergency that the rest of the world doesn’t see behind closed hospital doors. Now, that urgency has only heightened.”

Right now, blood product distributions to hospitals are outpacing the number of donations. Approximately 2,500 hospitals and transfusion centers across the country rely on the Red Cross to collect 12,5000 blood donations each day to meet the needs of their patients.

What is needed?

Donors of all blood types are urgently needed but there is an emergency need for platelet donors and type O blood donors. To make an appointment to give blood or platelets, donors can use the Red Cross Blood App, visit RedCrossBlood.org or call 1-800-RED CROSS or 1-800-733-2767.