The Fraser River continues to swell due to rapid spring thaw in B.C.'s Lower Mainland, prompting a new evacuation alert for properties under threat.

Residents of Barnston Island were not required to leave when the alert was issued Wednesday morning, but were told to prepare for the possibility.

However, they were warned to consider evacuating before the situation worsens, as the provincially-operated ferry that services the island will not be able to carry vehicles if the water rises much more.

Hundreds of horses, goats and cows were loaded on and off the ferry Wednesday as residents were advised to move livestock to an alternate location. No large animals will be allowed on the ferry once an evacuation order has been issued.

The unincorporated island located between Surrey and Pitt Meadows is home to about 155 people, one-third of whom live on a reserve, and is accessible by boat or ferry only.

While the alert is in effect, access to the island is restricted to residents, family members and business operators. The regional park is also closed.

The Metro Vancouver Regional District is responsible for emergency management on the island, and met earlier this week with the Katzie First Nation and other residents to share flood and response information. Anyone with questions can contact Metro Vancouver's Information Centre at 604-432-6200, or

Staff members are monitoring the rising river, patrolling dikes and using sandbags where needed, Metro Vancouver said. The province's River Forecast Centre, Emergency Management BC and Environment Canada all predict the river will continue to rise over the next several days due to early and sudden temperatures in the region, causing the snow to melt more quickly than usual.

The Barnston alert came a day after a similar warning was issued in the Township of Langley. On Tuesday, officials warned the areas of Northwest Langley, Glen Valley, Brae Island and McMillan Island were at risk of flooding.

Firefighters went door-to-door when the alert was issued, passing out information pamphlets to residents of 400 homes.

While residents of those areas have not yet been ordered to leave, campers staying at Edgewater Bar Campground were told to leave. One told CTV News the water rose 30 to 35 centimetres overnight.

A representative for Metro Vancouver Parks said the river rose right over some of the campsites, and that more were expected to flood on Wednesday.

Further east, a formal evacuation order was issued for a handful of properties in Chilliwack as the river surged Tuesday.

Residents of three properties were forced to leave their homes in the Carey Point area. Others nearby were put on alert.

Chilliwack said Tuesday that those located within the city's dike system should not be concerned.

In Maple Ridge, the city activated its Emergency Operations Centre and said it is closely monitoring conditions along the river. Crews will conduct daily dike inspections and information will be published on a dedicated website where residents can get details and sign up for email and smartphone notifications. 

First responders will be delivering flood advisories to about 50 homes and businesses along the Fraser River side of Wharf Street, which serves as the dike for the Hammond neighbourhood. Sandbags will be delivered to the west end of the street under the Golden Ears Bridge for residents in the flood advisory area to use.

Residents will be given an evacuation alert package should the river level exceed the 6.5 metre mark.

Current estimates suggest the Fraser will peak at 6.6 metres at the Mission gauge early next week, and further alerts and orders are possible in the coming days.

B.C.'s political leaders toured the affected areas from the air Wednesday.

"We've seen the water rising rapidly. Today we've seen that it's within a meter of causing an outright disaster," Liberal Leader Andrew Wilkinson said.

Premier John Horgan and Wilkinson held a news conference with the mayor of Chilliwack, two Liberal MLAs and a Green MLA in a warehouse packed with sandbags.

"Together, we MLAs have been travelling up the Fraser to take stock on what will potentially be one of the worst flooding seasons we've seen in British Columbia in a considerable amount of time," Horgan said.

"The snowpack has been unprecedented, the heat has been unprecedented, and so the levels that we were seeing at Mission were higher than they would be normally at this time of year."

He told reporters gathered in the valley that they saw the flooding as a non-partisan issue.

Those who are under evacuation orders must leave the area immediately, following the directions of local emergency officials. They cannot return home until the order has been lifted.

Residents whose properties fall under an evacuation alert do not need to leave, but are asked to gather essential items including medications, eyeglasses, valuable documents, immediate care needs and pets, and be ready to leave on short notice.

They're advised to know the location of all members of their household, and be prepared to help children, and those with disabilities or elderly people. Accommodations should be arranged if possible, though emergency housing will be provided if needed.

Pets and livestock should be relocated to a safe area immediately.

If time, residents should consider taking steps to protect their property from damage.

With files from CTV Vancouver's Breanna Karstens-Smith and St. John Alexander