Hurricane Irene
Hurricane Irene is on course to affect almost the entire U.S. East Coast -- a major and dangerous storm. REUTERS

Nassau County officials are urging people on the barrier island of Long Beach to leave before Hurricane Irene surges in over the weekend.

While the evacuations are voluntary -- unlike mandatory evacuations ordered for parts of Suffolk County and New York City -- Nassau County Executive Ed Mangano said that an exodus from Atlantic Beach, East Atlantic Beach, Lido Beach, Long Beach and Point Lookout should commence immediately.

Noting that the hurricane is expected to arrive on Sunday morning, Mangano said at a Friday press conference that the evacuation order could soon become mandatory. Gov. Andrew Cuomo also weighed in, reminding residents that Long Beach faces danger even if the order remains voluntary.

I think the voluntarily evacuation is the appropriate call at this time, Cuomo said in a call to the press conference. I also want to make sure we emphasize that just because it's a voluntary evacuation doesn't mean it's not serious. This is a very serious situation and just because it's sunny out and the weather looks fine, people should not take a false confidence.

Now is the time to evacuate, Cuomo added. Mangano echoed that, noting that This is a time to stay calm, be prepared, move orderly to higher ground.