Okanagan Basin Water Board – based in Kelowna is set to help Okanagan communities prepare drought plans:
Directors approved support for a drought planning project for the Okanagan. Work will now begin on determining the barriers and opportunities to get all Okanagan local governments to adopt appropriate drought plans for their community. This project is based on an extensive OBWB survey conducted last year that reviewed the state of existing plans in the valley and identified further work was needed.
Weather
The first week in May saw a cold low pressure system move across British Columbia, bringing cooler temperatures and scattered precipitation. Into the second week of the month, a blocking high pressure ridge developed over northern BC and this pattern has largely persisted. This has brought extremely warm, summer-like temperatures across the northern portions of the province (20-25˚C) and warm conditions through other areas. Thunderstorms over the period have been the primary source of precipitation through the month, leading to sporadic and localized rain events. Wide-spread rainfall has been limited in May.
Snow Pack
Warm weather through early May has led to rapid snow melt across the province. Most snow survey locations across the province experienced 50-200 mm of snow water equivalent loss over the May 1st to May 15th period. Current melt rates at snow pillows range from 5-25mm/day through most of the province, with some regions experiencing up to 30-40mm/day of melt.
May 15th snow basin indices have declined through most of the province since May 1st, and range from a low of 11% of normal in the South Coast and Vancouver Island, to a high of 122% of normal in the Nechako. May 15th snow basin indices have increased since May 1st in the Upper Fraser-East, Nechako, Lower Fraser, Upper Columbia, Boundary, and Central Coast.
Most regions of the province have extremely low May 15th snow basin indices (<49% of normal) (Figure 1). This includes the Middle Fraser, Lower Fraser, East Kootenay, Okanagan, Similkameen, South Coast, Vancouver Island and Peace. Below normal snow basin indices (50-79%) are present in the Boundary, South Thompson, West Kootenay and Stikine. Slightly below normal (80-89%) basin indices are present in the North Thompson, Upper Columbia, and Central Coast. Near normal (90-109%) snow basin indices are present in the Upper Fraser and Skeena-Nass basins. Above normal (>120%) snow pack conditions are present in the Nechako basin.
The average of all provincial snow water equivalent measurements for May 15th is 60% of average conditions. This is the lowest province-wide average for the May 15th bulletin in the past 31 years of record.
The extremely low snow pack this season is the result of warm winter and spring temperatures that have led to a higher than normal portion of the winter precipitation falling as rain rather than snow and high rates of early season melt.