2020 Fraser River Freshet Information
According to the BC River Forecast Centre, the overall snowpack for the Fraser River watershed as of April 1, 2020 is at 116% of normal, and some areas of the Fraser River watershed are significantly higher than normal.
Above average flows on the Lower Fraser River are expected this freshet, but the snowpack is only one element of seasonal flood risk during BC’s freshet season. Weather patterns including prolonged hot spells or widespread heavy rainfall during the snow melt season play a critical role in whether or not flooding occurs.
The River Forecast Centre has indicated the peak flow at Hope will likely be in the range of 8,000 to 11,500 m3/s. As a comparison, the peak flow in 2012 was 11,700 m3/s, which equated to a peak water level at Mission Gauge of 6.4m (approximately a 1:20 year event). In 2012, some areas in the unprotected floodplain outside the dike system experienced flooding, but the water levels were well within the range that Chilliwack's dike system is designed to withstand.
The river levels in 2012 also caused the local groundwater table to rise, which resulted in some water getting into basements in parts of Fairfield Island. Residents in that area should review steps they can take to minimize possible damage in the event the water table rises to a similar level this year, such as having a sump pump and moving items off the basement floor.
Higher flows than 2012 could occur this year depending on weather patterns in the coming months. The peak occurs between May and July, and the City will be closely monitoring conditions and forecasts.
Each year, regardless of snowpack conditions, the City undertakes spring flood preparedness measures including checking all flood protection infrastructure and reviewing and updating our Fraser River Flood Response Plan.
Information was provided in the presentation to Council on April 21, 2020.
Please also refer to these pages for more information:
For more information, please call our freshet information line at 604.793.2757.
|Fraser River Freshet Slides for Council - April 21, 2020||2020-04-21||843KB|