Bloodworks Northwest is urging blood donors to donate now and through the next two weeks, as supplies fall to emergency levels — a one-day supply or less.

The normal inventory is a four-day supply, according to Bloodworks Northwest.

“In the aftermath of the heat wave, our inventories have fallen by nearly 25 percent,” said James P. AuBuchon, president and CEO of Bloodworks. “Prolonged high temperatures and poor air quality kept donors at home, and for many blood types we are now looking at empty shelves.”

“With the solar eclipse on Monday and with up to 1 million people converging on Oregon and Southwest Washington, we need to be ready,” AuBuchon added. “Responding to emergencies requires blood that is already collected, tested, on the shelves and ready for immediate use.”

Only a four-day inventory allows the organization to respond immediately to emergencies, or to a dramatic increase in needs from local patients, according to Bloodworks Northwest.

Type O — which is the most common blood type in the Northwest — is being shipped to hospitals almost as soon as it is collected. People receiving emergency room care have also made extra demands on the tight supply.

“All regions of the U.S. are currently experiencing a shortage, so assistance from other centers is minimal,” AuBuchon said. “We’re relying on local donors to help us respond to this emergency.”

Donors can schedule an appointment at any donor center, including one in Lynnwood located at 19723 Highway 99 Ste. F, by going online at schedule.bloodworksnw.org or by calling 1-800-398-7888. People can also can check online at bloodworksnw.org to find dates and times of nearby mobile drives.

Blood collections usually fall by 15-20 percent during summer, with schools and colleges on break and donors on vacation — but the need for blood is often higher in summer from patients undergoing surgeries, ERs treating trauma victims, people having cancer treatment and surgeons performing organ transplants. According to Bloodworks Northwest, it takes about 800 donors a day to maintain a sufficient supply for the nearly 100 hospitals served by the organization.