B.C. snowpack surges well past ‘normal’ levels; flood watch to intensify as heat sets in

A few cooler than normal weeks delayed the melt of mountain snow, leaving large swaths of B.C. at a high risk of flooding.

According to the latest report from the BC River Forecast Centre, the June 1 snowpack is 165 per cent of normal across the province.

4:15 How Kamloop is preparing for possible spring flooding

Even the Okanagan, a region that once had a lagging accumulation of snow compared with the rest of B.C., had a snowpack of 153 per cent of normal as June got underway. Reporting the most significant accumulation is Stikine, which had a snowpack of 289 per cent of normal.

All of this is being attributed to spring temperatures 1.5 to 4 degrees cooler than usual, slowing the annual progression of melting snow.

“By June 1, on average, approximately half of the accumulated snowpack typically melts, according to data from automated snow weather stations,” the BC River Forecast Centre said in its monthly report.

2:24 Snowpack levels for the Okanagan are in the normal range

“Snowpack melt has been delayed by two to four weeks due to extended cooler weather in April and May, where only 19 per cent of the snowpack at automated snow weather stations has melted by June 1.

When it comes to concerns around flooding, however, attention will be focused on how quickly the heat rolls in, how intense it is and whether it’s accompanied by any rain.

The BC River Forecast Centre said the regions at relatively high risk due to snowpack include the Upper Fraser, Cariboo Mountains, North Thompson, South Thompson, Lower Fraser, Upper Columbia, the Kootenays, Similkameen and the northern regions of the province

“Other Interior regions like the Okanagan, Nicola and Peace remain at risk to extreme rainfall events,” the River Forecast Centre said.

Typically, according to the report, rivers on Vancouver Island and along coastal B.C. reach flood-level flows from heavy rain in the fall and winter and these areas are unlikely to see flooding in June from snowmelt, unless an extreme rainfall event occurs.