Forecasters are expecting the Okanagan to experience a drought this summer, which will be followed up by an extended wildfire season.
Government environment management officials say the drought will be brought on by lower than average snowpack accumulation this winter coupled with a two-to-four weeks head-start on the freshet melt at elevation levels below 1,500 metres.
But all that prognostication comes with one unknown wild card—how much precipitation falls on the valley during the rainy season from now through June.
If above average precipitation occurs, the concerns shift from drought to flooding, if lower than average precipitation the forecast drought hazards will only intensify.
Forecast predictions were part of a webinar presentation organized by the Okanagan Basin Water Board to hear presentations on surface water, groundwater and climate issues forecast for the valley this spring and summer.
Robert Warner, with the BC Wildfire Centre, said a repeat of the 2017 and 2018 wildfire seasons—which saw 1,216,053 hectares and 1,349,603 hectares burned respectively with a combined fire suppression cost of more than $1.2 billion— remains an uncertainty.
“The early freshet means a potentially longer fire season, we are seeing signs it will be busier than normal at this point already, but we still aren’t sure if 2017 and 2018 are the new normal yet or just outliers, but we are still concerned about this year for sure,” Warner said.
He alluded to spring rains being a factor as well, along with worries about thunderstorms sending lightning sparks on dry timber.
“Last year we had 70,000 lightning strikes across the province over a one week span in 2018 which presents challenges,” he added.
Dave Campbell, with the BC River Forecast Centre, echoed the realities of a relatively warm winter and snowpack currently 72 per cent below normal for April across the Okanagan, saying those conditions are favourable for reducing flood risks.
“But seasonal rainfall for that May and June period is a challenge to foreshadow what to expect…generally about 10 to 40 per cent of the Southern Interior spring runoff is generated from that rainfall component,” Campbell said.
Shaun Reimer, responsible for managing water levels for Okanagan Lake, said lake levels are currently 15 centimetres higher than average for April, which is positive given the drought outlook for summer.
“Precipitation remains the key going forward but we have some room to maneuver at this point. Rather than focus on water release, our outflow will be minimal as we will be looking to capture as much water as possible if drought conditions persist,” Reimer speculated.
Doug Lundquist, meteorologist with Environment Canada, said Vernon, Penticton and Kelowna are all below normal precipitation norms, a reflection of the dryer winter which was interrupted by an Arctic front in February that descended across the province bringing a burst of snow and colder temperatures.
“Our outlook at this point if for above average warmer temperatures for April through to June with the long range precipitation forecast being poor,” Lundquist said.