Issued: Nov 13th, 2019 at 13:00 PST
Weather Event Impacts:
· Localized flooding
· Increased risk of landslides and debris flows in prone areas
Timing:
· Early Saturday morning through mid-day Sunday
Key Points:
· An Atmospheric River will take aim at the BC Coast this weekend delivering heavy rainfall, strong winds and high freezing levels.
· Total rainfall amounts are currently forecast between 90 and 140mm over the 36-hour period spanning early Saturday morning to mid-day Sunday.
· The heaviest rainfall is expected over west facing slopes and tributaries including:
o West Coast of Vancouver Island from Ucluelet to Winter Harbour including Zeballos
o Central Coast and North Coast from Kingcome Inlet up to Kitimat
· The North Shore Mountains and Howe Sound will also see heavy rain although somewhat less in the 50-100mm range.
· Strong southerly winds with gusts up to 90km/h are forecast along exposed coastal sections of West Vancouver Island, the Central and North Coasts on Saturday. Haida Gwaii and the North Coast could see even stronger gusts in excess of 100km/h on Saturday.
· There is currently 20-30 cms of snow on the ground of the central Coast Mountains above 1600 metres.
· Given the tropical origin of the Atmospheric River, freezing levels will rise above 2500 metres by Saturday afternoon resulting in rain on snow for the Central Coast mountains.
· The heavy rain and melting snow will result in elevated runoff and rising river levels.
· The River Forecast Centre will monitor streamflows and high streamflow advisories or flood watches may be issued.
· A drier pattern is expected from Sunday evening onwards with seasonal temperatures and freezing levels returning to approximately 1000m.
Forecast confidence:
High – regarding the wet and windy pattern.
Moderate- total rainfall amounts will depend on the duration of the Atmospheric River. A faster passing system would yield lesser amounts. Please monitor weather alerts and streamflow advisories.
For updates, please monitor upcoming weather forecast and possible warnings:
Weather Alerts: www.weather.gc.ca/warnings/index_e.html?prov=bc
BC River Forecast Centre Flood Warnings & Advisories: http://bcrfc.env.gov.bc.ca/warnings/index.htm
ECCC Daily Weather Blog: www.avalanche.ca/weather