2020 Fraser River Freshet Information
July 15, 2020 Update:
The 2020 Freshet consisted of a number of Fraser River peak water levels as registered at the Mission gauge as follows:
• May 31 - 5.3m
• June 5 - 5.4m
• June 29 – 5.9m
• July 7 - 5.8m
The highest water level on the Fraser River occurred on June 29 and was recorded as being 5.9m at the Mission gauge.
The spring snowpack for the entire Fraser River basin was above normal (117% in March). Cooler than normal temperatures in May and June resulted in delayed snow melt which caused river levels to remain only slightly above normal as opposed to a rapid snow melt like we experienced in 2018.
July 2, 2020 Update:
Above average flows on the Lower Fraser River are expected this freshet, and the snowmelt 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.
As of July 2, 2020, the provincial River Forecast Centre has indicated the peak flow at Hope will likely be in the range of 11,000 to 12,000 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 weeks. The peak typically 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|