Desperately dry

East Kootenay snowpack at 42 per cent of normal; provincial average 53 per cent

Cooler temperatures this week brought some rain and even a bit of snow at higher elevations in the East Kootenay, but overall the snowpack is at record lows for May.

This is the word from the latest snow bulletin on May 9 from the BC River Forecast Centre.

The latest report says the snowpack is at 53 per cent of normal for this time of year. That’s a provincial average with individual reports ranging from 10 to 100 per cent of normal. The average is a new record low (measured since 1980), and is 13 per cent below the previous low of 66 per cent, recorded in 1980.

The East Kootenay snowpack is at 42 per cent of what you would normally see at this time of year.

Of the 183 snow survey measurements made for the May 1st period, 33 stations, or 18 per cent, observed new record lows, with many locations having 40 to 50 years of record. Low and mid-elevation snow is largely gone for all areas of the province with snow remaining only at high elevation, the report says.

The advance in runoff timing is expected to continue to lead to earlier timing of peak flows and recession to the low-flow season across the province. The shift in timing echoes the pattern in snow melt, with many rivers experiencing flow conditions that are three to four weeks or more ahead of normal.

As for the outlook, the report says strong El Niño conditions that developed over the equatorial Pacific regions over the past few months peaked in the winter and are declining. The Climate Prediction Centre (CPC) at the U.S. National Weather Service/NOAA is forecasting El Niño (ENSO) conditions to transition into neutral conditions by late-spring/early summer 2016, and an increasing likelihood of moving towards La Niña conditions into the fall/winter of 2016. In the northern Pacific Ocean, below normal sea surface temperature anomalies have replaced the “blob” of warm water that persisted last year. However, near-shore water along the BC, Washington and Oregon coasts remains warmer than average, with warm-phase Pacific Decadal Oscillation (PDO) patterns being observed.

Seasonal forecasts from Environment Canada are indicating an increased likelihood of above-normal temperatures across British Columbia over the May to July period, and into the extended forecast period of the late summer months.

With significant snow melt already occurring, many river basins are approaching, or have passed, the peak of the freshet season. In mid-sized watersheds with limited high elevation terrain in the south and central interior, the peak of the freshet season may already have occurred. This includes the Similkameen River, tributaries in the Okanagan basin, Salmon River, Nicola River upstream of Nicola Lake, and similar surrounding rivers. In the larger river systems of the province, and rivers that drain higher elevation alpine terrain, the peak flow season is expected to continue to be 3-4 weeks earlier than normal, but have not yet occurred.

The advanced freshet is expected to put pressure on summer low flows in snow-melt dominated rivers across the province. With the current very low snow packs remaining in the Upper Fraser, Middle Fraser, Nechako, Similkameen, East Kootenay, Central Coast, Stikine, Skeena, Liard, and Northwest, the risk for low flows this summer are elevated.