What happens in the upper Fraser River watersheds can affect the lower part of the river in communities like Chilliwack.

What happens in the upper Fraser River watersheds can affect the lower part of the river in communities like Chilliwack.

City readies Chilliwack for melting snowpack

Properties outside dike protection in Chilliwack could be affected if there's a sudden heat wave or heavy rain in the coming weeks.

Chilliwack properties outside city dike protection could be affected if there’s a sudden heat wave or heavy rainfall during the 2012 spring freshet.

That was the message at city hall Tuesday in the wake of news from B.C. River Forecast Centre that the overall snowpack is higher than normal in the Fraser River watershed.

The high snowpack is looking comparable to the 2007 situation, when many homes and businesses were sandbagged against the threat of flooding.

The overall Fraser basin snowpack is at 131 per cent, according to a 2012 freshet update presented by staffer Tara Friesen.

Runoff volumes and peak flows of melted snow water will actually depend on how the weather plays out in the coming weeks.

“What we don’t want to see is a long, cool spring, and then all of a sudden a hot period with temperatures of more than 25 degrees for more than a week, or heavy rains,” Friesen said.

Either of those scenarios would cause water levels to rise quickly.

What happens in the Upper Fraser and Thompson is of critical importance to Lower Mainland communities.

“They tend to influence the peaks we see down here,” said Friesen.

But despite those facts, Chilliwack and other cities on the Fraser will get plenty of advance notice, as it takes a few days travel time for the water to works its way down to the lower Fraser. So it could be a week or more, she said, and there would be advisories and alerts issued in the case of high water or bank full conditions.

Chilliwack’s flood response planning included $9 million in dike upgrades, offering protection of up to 8 metres at the Mission gauge, she said.

Recent flood protection projects included dike raising, bank protection work and improvements to the dike’s seepage control system.

“The City has prepared emergency plans and maintains an emergency management organization,” said city spokesperson Starlee Renton.

“This is to ensure the safety of citizens when the situation requires a high level of response. Snowpack levels and runoff forecasts will continue to be closely monitored and you will be provided with information updates as they are received.”

Residents were reminded to have their grab-and-go emergency kits ready.

Find updates at www.chilliwack.com/floodprotection, follow www.twitter.com/city_chilliwack or www.facebook.com/chilliwack.

Residents can call an information hotline at 604-793-2757.