Category Archives: Wet

UPDATE 2:45PM Tuesday – High Stream flow Advisory Issued for Port Alberni area – Rainfall Warning Continued

UPDATED 2:45PM Tuesday
The River Forecast Centre issued a High Streamflow Advisory for the Port Alberni region at 1:30PM this afternoon.

Here is the text:

ISSUED: February 14, 2016 1:30PM

The BC River Forecast Centre is issuing a High Streamflow Advisory for Vancouver Island including:

Central Vancouver Island including streams and rivers in the Port Alberni and surrounding areas
A strong Pacific storm is expected to spread heavy rain across Vancouver Island and south-west BC Wednesday evening and through the day on Friday. Total rainfall amounts of 90-120 mm, and potentially more over higher terrain, are currently forecasted from Tuesday evening to Thursday morning. Temperatures are expected to remain high throughout this event, with freezing levels generally above local mountain top level. In addition to heavy rainfall, melt of snow in low elevation areas is also expected, and will contribute to streamflow runoff. At high elevations, deeper snow will be able to absorb much of the rain and energy from the warm temperatures.
High streamflow is expected throughout the region on Wednesday, and potentially into Thursday morning. At this point, forecasts are not indicating the potential for rivers to reach flood stage, however low-lying areas may experience minor flooding. With snow at low elevations, minor flooding is also possible in areas with poor drainage or where drainage is impeded by snow.
The public is cautioned to stay clear of rivers and riversides during the high streamflow period because the quickly flowing water and the adjacent riverbanks are potentially unsafe.

 

And here is the Rainfall Warning from Environment Canada

10:46 AM PST Tuesday 14 February 2017
Rainfall warning in effect for:

Inland Vancouver Island
Rain, at times heavy, is expected.

A strong Pacific front being fueled with energy and moisture from the subtropics will spread heavy rain to West and Inland Vancouver Island this afternoon.

The front will stall tonight through Wednesday resulting in a prolonged period of heavy rain.

For West Vancouver Island total rainfall will be 130 to 170 mm by Thursday morning.

For Inland Vancouver Island total rainfall will be 90 to 120 mm by Thursday morning.

The heavy rain will taper off on Thursday morning as the front finally moves eastward out of the area.

Heavy downpours can cause flash floods and water pooling on roads. If visibility is reduced while driving, turn on your lights and maintain a safe following distance.

Rainfall warnings are issued when significant rainfall is expected.

The rain should begin about 1PM and intensify this evening with the strongest rainfall in the 8PM hour.

The UWash confirms the rain warning amounts with up to 120mm (black) falling in 24 hours between 4PM Tuesday/Wednesday. 200mm in the mountains.

Another 30mm is expected from Wednesday to Thursday afternoon.

The snowpack *should* absorb this rain. But there is potential for high river flows and flooding.  So beware of that.

I will update if anything major vhanges.

Happy Valentines Day!

Next up: Jet Stream and Atmospheric River. Special Weather Statement Issued

It has been a glorious Family Day afternoon once the fog lifted!

I hope you were all able to soak up those rays of sunshine, because in the next 24 hours it’s going to be soaking in a different way.

Here is the text from the Special Weather Statement just issued by Environment Canada for Inland Vancouver Island.

A Pacific frontal system associated with a stream of sub-tropical moisture will bring a prolonged period of rain to the BC South Coast beginning late Tuesday, along with the potential for strong winds.

Uncertainty remains concerning the development and track of this frontal system, which are important factors determining the location of heaviest rainfall and strongest winds. However, there is good confidence that heavy rain will begin late Tuesday. Coastal and west facing slopes have the potential to exceed 100 mm of rainfall from late Tuesday through early Thursday.

Freezing levels will remain above 3000 metres at the coast and many alpine areas will see heavy rain. The snowpack is expected to absorb this rain event mitigating river flooding impacts. The River Forecast Centre will be monitoring this rain event and may issue a high streamflow advisory (http://bcrfc.env.gov.bc.ca/warnings).

At lower elevations, especially in the Fraser Valley, local low land flooding could be a concern as melting snow on the ground combines with the expected rainfall accumulations. Keep drains free of ice or debris.

Strong winds combined with heavy rain may lead to power outages.

Here is what the latest from the UWash model says about timing and intensity for Vancouver Island.

Rain is expected to begin before 1PM on Tuesday and will intensify in the 7-10PM period with up to 16mm falling in that 3 hours and every three hours from then until 7AM Thursday,

That means in that 12 hour period between 7PM Tuesday and 7AM Wednesday we could see as much as 64mm of rain.

The image below shows up to 65mm of rain (pink) falling in the 24 hours between 4PM Tuesday and 4PM Wednesday.  Or up to 130mm (black) of rain falling at higher elevations.

It will continue to be rainy and drizzly through Wednesday evening and Thursday but we should hopefully dry out for the weekend.

We might also see some gusty winds, but most of the heaviest winds seem to be focused on the North Island on Tuesday and Oregon and Washington State on Thursday.