TORONTO, Aug 5 (Reuters) - Water has begun to overflow

over a natural dam created by a landslide blocking Chilcotin

River, British Columbia officials said, triggering evacuation

orders for people along the banks of Chilcotin and Fraser rivers

in western Canada.

Bowinn Ma, B.C.'s Minister of Emergency Management and

Climate Readiness warned of additional landslides as the water

gushing through the channel picked up pace carrying debris.

"The likelihood of a worst case scenario is decreasing,

but make no mistake, the risks are still there," she said in a

media briefing.

"Now is not the time to go boating. Now is not the time

to go take a look at the water."

The water began to trickle over the natural dam Monday

morning at 7.5 cubic metres per second and the pulse rose to 750

cubic metres per second by 1330 pacific time (1630 ET/2030 GMT)

as the water began to gush, increasing the size of the channel

and carrying large wooden debris and sediments.

Officials are closely watching the situation and warned

the pulse of water could increase as a large amount of water

stored behind the natural dam is discharged.

Evacuation alerts have been issued in Cariboo,

Thompson-Nicola regional districts in remote parts of western

Canada, as officials urged the local population and tourists to

stay off the river and the banks.

The region has been under watch since Wednesday after a

landslide blocked the river in the region, creating worries

about flooding and triggering emergency alerts to ensure

communities are ready to move to safer areas.

Even if the water elevation in an area may be similar to

spring flooding levels, the water will react differently with

greater momentum and force, than a gradual increase in water

levels, officials said.

Nathan Cullen, B.C.'s minister of water, land and resource

stewardship said the government was aware of the threat on wild

salmon and fish species, as well as cultural sites along the

rivers and was working with partners to prepare to go to sites

once it is safe to do so.