Blood donations have been down over the last month.

According to Canadian Blood Services, winter conditions and seasonal illnesses are at the heart of the drop.

“In fact, in January we had to cancel 16 donation events,” said CBS vice-president of donor engagement Ron Vezina in a press release. “And we know that road conditions and illness have prevented many donors from attending their appointments.”

Vezina said hospitals have the blood they need today, but the situation could change if a consistent supply can’t be collected.

He said a six-day period ending earlier this week saw 1,500 fewer donations than expected.

“Blood is perishable, so a constant, fresh supply is vital,” Vezina said. “New donors of every blood type are needed each day to keep pace with ongoing hospital need, and to help stay prepared for emergencies.”

CBS is calling on Canadians to donate blood or plasma as soon as they can.