An evacuation order in Cache Creek, B.C., has been expanded Monday after a violent storm tore through the province's Interior, leaving a trail of flooding and destruction.

The evacuation order affecting about 40 residents came after Mayor John Ranta declared a state of emergency on Sunday.

It will keep people away until crews are able to assess the stability of the slopes above residences that are deemed at risk from flash floods and debris flow.

Some people will likely be allowed to returned briefly to a riverside trailer park where several homes were washed away, to gather their belongings with a police escort, but it could be weeks or even months before some residents are allowed to move back home, said Ranta.

"We'll do our best to ensure that they're allowed back as quickly as possible if [their homes] are deemed to be safe," he said.

Another 80 residents remain under an evacuation alert, meaning they must be ready to leave at a moment's notice.

Provincial assistance provided

The B.C. government announced on Monday that disaster financial assistance is available for eligible applicants from the Cache Creek area — including homeowners, tenants, small business owners, farmers and charities — that were unable to obtain insurance to cover disaster-related losses.

Applications for assistance must be submitted to Emergency Management BC by Aug. 24, 2015. 

Financial assistance is provided for each accepted claim at 80 per cent of the amount of total damage that exceeds $1,000, to a maximum amount of $300,000.

Ranta said he hopes many homeowners not covered by insurance will receive money from the province for rebuilding.

"Imagine how devastating it would be to lose your home to a rainfall event and not have insurance coverage," he said.

As of Sunday evening, about 60 homes in the village of about 1,000 had been abandoned and nearly 120 people had registered at the emergency operations centre.

On Sunday, B.C. Premier Christy Clark tweeted her support for residents affected by the flooding.

Local member of the legislative assembly Jackie Tegart said the situation is especially devastating for a semi-desert settlement like Cache Creek, which is unaccustomed to high levels of rainfall. But she noted that the community was banding together to recover.

"Small communities help each other," said Tegart. "And certainly from what I've seen and heard from people on the ground that's exactly what's happening."

Rain and hail flood village

On Saturday, an estimated 30 to 40 millimetres of rain and hail fell on the area in a single hour, sending detritus-strewn mud and water pouring through the community's streets and shutting down two highways.

Ranta said he was in his car when the storm began shortly after 4 p.m. on Saturday, and that by 6:30 p.m. the village was devastated.

"It started off as a trickle that was going down the storm sewers, to a river that was running down the road with debris floating along," he said, describing the intensity of the rainfall as "unbelievable."

"It was raining just like you can't describe — rain combined with hail, coming down like the sky was falling."

Charlene Milward's 2,000-square-foot home is one residence where insurance may not cover the damage.

Her home was shoved off its foundation and the basement was filled with mud.

"She's pretty numb right now," said her mother, Cheryl. "She's in disbelief."

Cache Creek, B.C., map

The flash flood hit the B.C. Interior community on Saturday afternoon.

With files from The Canadian Press