(CNN) — The American Red Cross is sounding the alarm that the United States’ blood supply has fallen by nearly 25% since early August, to what it describes as “critically low levels.”

The organization, which provides about 40% of US blood and blood components, announced on its website Monday that this national blood shortage is potentially threatening the medical care of patients who might have an emergency need for blood or those who depend on lifesaving blood transfusions for conditions such as cancer or sickle cell disease.

As donor turnout fell in August, the Red Cross announced that it saw a shortfall of about 30,000 donations last month alone, amid a busy summer travel season and back-to-school activities.

In its announcement, the Red Cross also pointed to “back-to-back months of worsening climate-driven disasters” as further straining the blood supply since some blood drives had to be canceled due to extreme weather, for instance.

Just a couple of weeks ago, Hurricane Idalia caused more than 700 units of blood and blood platelets to go uncollected in the southeastern US, according to the announcement. Currently, the Red Cross is keeping a close watch on Hurricane Lee and its potential impact on the Northeast region of the country later this week.

“For so many patients living with urgent medical care needs, crises don’t stop with natural disasters,” Dr. Pampee Young, chief medical officer for the American Red Cross, said in Monday’s announcement.

“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,” Young said. “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.”

Overall, the distribution of blood products to hospitals is outpacing the number of blood donations being made, and according to the Red Cross, about 2,500 hospitals and transfusion centers nationwide rely on the nonprofit to collect around 12,500 donations each day to meet patients’ needs.

Volunteers can make appointments online to give blood or platelets at the website RedCrossBlood.org or by calling 1-800-RED-CROSS.

In early August, the Red Cross announced that more gay men were eligible to give blood, as a more inclusive risk-based individual assessment to determine whether someone is eligible to give blood, regardless of sexual orientation, sex or gender, would be used. Historically, gay and bisexual men were banned from donating.