Time is running out for millions of people bracing for Hurricane Michael as it barrels toward the Gulf Coast.

"This is a massive storm, we've never seen anything like it in the panhandle," said Florida Governor Rick Scott.

Michael could make landfall as a Category 3 storm Wednesday, packing a storm surge of 8 to 12 feet. The governor now declaring an emergency in 35 Florida counties, activating hundreds of National Guard troops.

Residents are filling sand bags, boarding up windows and stocking up on supplies.

"We weren't nervous last night when we went to bed. Then when we woke up this morning and all of a sudden it was first a Cat 2, then it looks like it's going to be worse than that, so we're a little nervous," said resident Cole Lauzau. 

Mandatory evacuations are now being ordered for parts of the panhandle, but there are concerns that some of the shelters in the area won't be able to withstand the heavy winds. In a Facebook post, the Wakulla County Sheriff's Office warning no shelters will be open because the county's shelters are safe only for a category two storm.

"Every family must be prepared. Every family. Remember, we can rebuild your house, but we cannot rebuild your life," said Governor Scott.

In the gulf, cruise ships are altering their routes. Some oil and natural gas platforms are shutting down. Back on land - the air force is relocating aircraft at a base near Panama City to Ohio, far away from the storm zone.