A heavy rain warning has been issued for the Lower Mainland, according to the watch commander for Mainroad Contracting.
“A weather event is anticipated to impact the Lower Mainland within the next 24 hours. In anticipation, Mainroad will be patrolling for flooding problems on all highways until the event passes, roadways are clear and back to normal.”
Mainroad’s 24-hour communications and dispatch office will pass on observations and concerns to crews when contacted.
According to Environment Canada, 40 to 50 millimetres of rain is expected to fall at Pitt Meadows airport Sunday night, with the temperature rising to 10 C by morning.
The rain is expected to cease in the afternoon Monday. The forecast for later that day is a 30 percent chance of showers, with another 10 to 15 mm, and a similar amount overnight.
Rain is expected throughout next week.
As well, a high streamflow advisory, issued by the River Forecast Centre for the South Coast, remains in effect.
The advisory is for: Howe Sound, including the Stawamus River and surrounding creeks and tributaries; Sunshine Coast, including streams around Gibsons, Sechelt and surrounding areas; North Shore Mountains, including the Seymour River and surrounding creeks and tributaries; and the Lower Fraser Valley, including the Chilliwack River and surrounding creeks and tributaries.
“An atmospheric river storm event is expected to impact the south coast of British Columbia Sunday and Monday. Rainfall amounts are forecast between 50-200mm. Freezing levels are expected to rise into the 1,500-2,000 m range during the storm. Snowmelt from mid-elevation terrain may add to runoff for this event. In watersheds with higher terrain, including the Squamish River and Lillooet River, snow may be the dominant form of precipitation, and river responses are expected to be lower than more coastal areas.”
River levels are expected to rise rapidly in response to heavy rain. High streamflow is expected on rivers throughout the region, with the highest flows expected on Monday and possibly Tuesday.
The River Forecast Centre will continue to monitor conditions and will update the advisory as conditions warrant.
• Mainroad Communications and dispatch: 604-271-0337.