With the melt comes the water

As the weather warms and the snowpack begins to melt, there are a few concerns for inland portions of the northwest and how the record snow pack will affect the areas of the Skeena, Bulkley and Nechako basins.

Jeremy Hainsworth of the Canadian Press put together a piece on the potential danger areas.

Potential for B.C. flooding remains as record snowpacks begin to melt
Jeremy Hainsworth
Canadian Press
Sunday, March 11, 2007

VANCOUVER (CP) - B.C.'s Ministry of the Environment says the potential for flooding remains high along the coast and in the Skeena, Bulkley and Nechako basins of northern B.C. as record snowpacks begin to melt.

But, says director Des Nobels of the Skeena Queen Charlotte Regional District, any problems on the Skeena, at least, would be inland of Terrace.

"All of that flooding would take place upward of the tidal mark," Nobels said from his coastal home outside Prince Rupert, which sits on the Skeena estuary. "There's nothing that would affect Rupert itself."

Terrace is 120 kilometres east of Prince Rupert.

The ministry also says the Fraser River holds a high potential for flooding as snowpacks on the south, mid and north coast, Vancouver Island and the lower Fraser River are 135 to 145 per cent of normal.

And that has led to calls for government action along the lower Fraser, which runs through portions of the Lower Mainland.

NDP public safety critic Mike Farnworth says the matter needs to be dealt with now, not when the river breaks its dikes.

Public Safety Minister John Les has said his ministry is working hard to address the threat.
He has told the legislature that his government is consulting with municipalities, regional districts and First Nations to locate the weak spots.

The ministry is also forecasting well-above-normal spring runoff in the Thompson and Peace river basins.

And, says the ministry, while the flood risk throughout the province has moderated over the past six weeks as a result of the easing of snowfall, significant flooding potential remains.

Because of a "robust" start to winter - with heavy snowfalls from October through mid-January - officials say most river basins in B.C. had accumulated above-normal or well-above-normal snowpacks as of March 1.

Areas such as the Okanagan and Kootenays have near-normal snowpacks, but there are no areas of B.C. with below-normal snowpacks, the ministry says.

A release from the ministry says whether flooding occurs depends on a number of factors, including the amount of additional snow that falls during the remainder of the winter, and weather conditions during snowmelt in May and June.

Vancouver Island and other coastal drainages such as the Chilliwack River, Alouette River and Squamish River are excluded from spring flooding concerns.

Those drainages normally experience their high flows during fall and winter rain storms, not from spring snowmelt.

North-central B.C., and the Nechako, upper Fraser, Peace and Skeena rivers are all in the 130 to 150 per cent of normal range.

NDP forestry critic Bob Simpson warned last month that the high snowpack in the region south of Prince George combined with the giant swath of trees killed by the mountain pine beetle may prove to be a recipe for disaster this spring.

"The mountain pine beetle epidemic is changing the hydrology in the entire Fraser basin and throughout B.C.," Simpson said.

"The threat of flooding from larger-than-normal snowpacks will be significantly compounded by huge tracks of dead pine forests and massive clearcuts as a result of the pine beetle infestation. The vast majority of the snowpacks will now run directly into the rivers."

He accused the provincial government of worsening the situation by failing to develop a harvesting plan that would take into account the impacts of mountain pine beetles on hydrology.
"That mistake will mean more of the snowpack will go straight into our river system without the moderating effects of living forest ecosystems," he warned.

Forests and Range Minister Rich Coleman accused Simpson of being alarmist.

Much of the rest of the Interior - including the Middle Fraser, Quesnel Highlands, Similkameen, Columbia, Nicola/Coldwater and lower Fraser regions - has well-above-normal snowpacks in the 110 to 130 per cent of normal range.

The North Thompson and South Thompson are 114 per cent and 110 per cent, respectively.

The Fraser River watershed snow index is 125 per cent of normal. This is the fifth or sixth largest Fraser River snowpack measured since 1953, when detailed snow measurements in the Fraser began.

The ministry says the greatest risk for flooding results from above-normal snowpacks combined with well-above-normal temperatures and/or heavy rainfall during snowmelt in May and June.
Areas of concern should this combination be met are:

-All of the Fraser River and its tributaries, from its headwater areas above Prince George to the Lower Mainland.

-The Thompson River and tributaries.

-Rivers within the Peace and Nechako basins.

-The Skeena and Bulkley rivers and their tributaries.