RICHMOND, Va. (AP) — Officials say the catastrophic flooding from Harvey has increased the need for blood donations.

Virginia Blood Services said in a news release this week that many blood drives have been canceled and donor centers have closed in the affected areas. It notes that with more sustained rain in the forecast, those cancellations and closures are likely to rise.

Virginia Blood Services Executive Director Todd Cahill says donations also dramatically decline across the country around Labor Day because of the holiday weekend.

The release says type O blood donations are the most critically needed.

Virginia Blood Services is a nonprofit that provides blood products and transfusion-related services to Virginia, Washington, D.C., and West Virginia.