Approximately 200 people are stranded at a campground in northern Alberta after flooding washed out the only highway with southbound access.

An evacuation order was issued for the area of Marten Beach, including the hamlet and neighbouring campground on Thursday afternoon because of the flooding.

About 75 people from the hamlet have registered at the evacuation centre at the Municipal District Office, but hundreds of people at the campground haven’t been able to leave.

The group stranded at the campground includes Jesse Cummings and his fiancé, Ashley. They are in Marten Beach to get married this weekend, but some guests, including the best man and the officiant, are struggling to get there.

"The tougher the wedding, the stronger the marriage," Cummings told CTV News Edmonton.

High waters washed out Highway 88 north of the hamlet, cutting off access to the campground by road, despite some preparations by local authorities.

"We began sandbagging efforts ... thinking we were going to have just a little bit of water come down," said Murray Keric, reeve of Lesser Slave River. "It didn't take long to realize there wasn't enough sand bags in Alberta to slow this down."

Officials are using boats and quads to reach those campers trapped at two campgrounds in between the collapsed highway.

Crews are waiting for water levels to drop before they can assess the highway and start repairs; however there is rain in the forecast for Saturday.

Keric says the weather tower in the area measured 185 millimetres of water during the storm on Wednesday that caused the flooding.

Marten Beach is about 290 kilometres north of Edmonton.

With files from CTV News Edmonton's Jeremy Thompson