Early snowmelt in B.C. points to elevated drought hazards

The B.C. River Forecast Centre says conditions in British Columbia points toward elevated drought hazards in the province.

B.C.'s snowpack sits at 61 per cent of normal levels as of May 15, the centre wrote in its latest report, down from 71 per cent on May 1. 

Those lower levels are a reflection of the fact that snow is melting earlier than normal, the report said, primarily because April was warmer than normal.

Thirty-six per cent of B.C.'s snowpack had melted by May 15, the report said. In a typical year, 21 per cent of the seasonal snowpack has melted by mid-May.

Darius Mahdavi, CBC's science specialist, said early snowmelt can lead to less snow to feed reservoirs later in the season.

"The snow is sort of like a backup for the rain," Mahdavi said. "If we don't get rain, but we still have snowpack melting it sort of can compensate for that a bit. If we don't have the snowpack, there's no backup."

The centre said there is no elevated flood hazard given current snowpack levels, but higher flows are possible if there is heavy rainfall.

A provincial drought monitoring survey issued Thursday said cooler and wetter weather over the past week has improved drought conditions and boosted streamflows, especially in the province's southern coastal areas, but said rises in streamflow due to snowmelt can mask drought conditions.

"Streamflows may decline quickly once snowpack has fully melted if significant rainfall does not occur," the survey said.

Mahdavi says drought conditions in the northeastern corner of B.C. are the most worrying, with the basins at Fort Nelson and North Peace at drought Level 3 and the East Peace basin at Level 4 on a scale that ranges from zero to five. 

The survey paints a slightly more optimistic picture for western B.C., Mahdavi says, with drought conditions improving in the Lower Mainland, Sunshine Coast, Vancouver Island and Haida Gwaii.