Issued: January 8, 2021 at 15:10 PST
Weather Event Impacts:
· Localised flooding due to heavy rain adding to recent high rain totals and groundwater saturation
· Possible low land flooding as has been experienced in the recent week
· Power outages possible due to strong winds causing damage to trees
· Possible storm surge concerns due to king tides early next week (communities adjacent to Salish Sea)
· Elevated landslide and washout risk to vulnerable slopes and culvert infrastructure
· Disruption to marine transportation due to strong winds and rough seas
· Beginning Sunday and ending Wednesday (January 10 – 13th 2021)
· Multiple Pacific low pressure systems will move onto the BC coast over the next several days
· All of the B.C. coast saw a wetter than average December and early January.
· Impacts have been tied to the length of the active storm cycle on the coast dating back to early to mid-December and are forecast to continue into next week.
· The active storm pattern in the Pacific Ocean continues on the B.C. coast in its path.
· Low pressure systems will bring multiple rounds of strong winds and moderate-heavy precipitation.
o Prelude: Saturday there will be a first frontal wave over most of the coast ending on Sunday late morning.
o First Act: Sunday evening & Monday, expect another wet and windy system affecting the entire coast. This system taps into subtropical moisture and will generate intense rainfall.
o Crescendo: late Monday into Tuesday, another Atmospheric River will again barrel into the coast and bring heavy rain and strong winds.
· There is a lot of uncertainty about the exact timing each of these storms, but they will come frequently, occurring almost on a daily/nightly basis until middle of next week.
· Preliminary rain totals: Widespread 100+ mm/ 96 hours and higher totals still for SW facing slopes, ranging from 150-200+ mm of rain/ 96 hours (Sunday into Wednesday)
· Winds: Sunday and Monday – strongest winds (warning level winds 90+ km/h) north of Vancouver Island up to Haida Gwaii
Tuesday – strongest winds seem to mostly affect south of the Central Coast and Vancouver Island.
· Outlook: a relative weather pause on Wednesday and part of Thursday but there are indications that more storms are brewing for late next week as well. For the South Coast, a quieter period looks to take shape late next week into the weekend.
· The River Forecast Centre (RFC) may issue advisories if required as the event draws nearer.
· Preliminary storm surge is estimated by Dr. Scott Tinis at 40 cm for Point Atkinson on Tuesday 12th January, he points out that Courtenay/BC Hydro might be interested due to the potential for flooding around the river discharge.
High – regarding the stormy pattern.
Low – regarding timing, wind speeds and precipitation amounts.
For updates, please monitor upcoming weather forecast and possible warnings:
Weather Warnings: www.weather.gc.ca/warnings/index_e.html?prov=bc
ECCC Daily Weather Blog: www.avalanche.ca/weather
River Forecast Centre Advisories: http://bcrfc.env.gov.bc.ca/warnings/index.htm
BCHydro Power Outages: www.bchydro.com/safety-outages/power-outages.html
Storm Surge BC: http://stormsurgebc.ca/