A flood watch has been issued for the East Kootenay ahead of a that bears similarities to the one that caused the flood of 2013, which particularly devastated Calgary, Alta.
There鈥檚 three levels for the river forecast centre advisories and warnings, starting with high streamflow advisory, then flood watch and then flood warning.
A high streamflow advisory means river levels are rising or are expected to rise rapidly, but that no major flooding is expected. A flood watch means there is a potential likelihood that rivers will rise and flood beyond their banks. A flood watch is typically reserved for times when a flood is either happening or is about to happen.
鈥淭o go with a flood watch ahead of a high streamflow advisory is fairly telling in terms of just how strong of a system this is that鈥檚 moving in,鈥� said Jonathan Boyd, hydrologist with the River Forecast Centre. 鈥淚t is a very similar setup to 2013, where that system led to the pretty well devastating flood in Calgary.
"It was a wraparound, low-pressure system that swings in through Alberta and then comes back to hit the Rockies and hits the side that is usually on the lee-side that doesn鈥檛 necessarily get the rainfall."
In 2013, Boyd said there was spillover from that system and the Elk River near Fernie ended up getting very high. He said the expectation now is that the areas on the Alberta side of the Rockies are going to get the heaviest rainfall this weekend.
Boyd said that talking to Environment Canada at around 2 p.m. MST on Thursday, June 19, he heard some areas may get 100 to 140 millimetres of rain, but potentially up to 175.
鈥淚t looks like the heaviest totals are just south of Sparwood, the southern corner there,鈥� Boyd said. 鈥淥nce you get into the Cranbrook, Kimberley areas the more likely scenario is about 30 to 50 millimetres. So I wouldn鈥檛 say that flooding is as major of a concern for Cranbrook and Kimberley as it could be for Fernie, or particularly in the upper Columbia as well, the areas that are really on the border to Alberta are probably at the highest risk.鈥�
As flooding of areas adjacent to affected rivers may occur, residents who live near rivers or streams may want to consider taking precautions, including moving important possessions out of basements.
"[This storm's] so diverse in terms of every location and the specifics, so say the actual larger Kootenay River, probably not likely to get to flood levels from this particular rainfall event," Boyd said. "It鈥檚 ones that are larger that typically would be at a higher flow for seven or eight days of hot weather in the spring.
"We are now at least fortunately experiencing some cooler temperatures and have essentially pushed through all the main snowpacks, so in general, rivers have been flowing and dropping down over the past five to six days or so, after having some fairly hot weather in May and the start of June."
Working in Fernie and the Elk Valley's advantage is the fact that there have been very dry conditions leading up to this. Boyd said provincial drought levels were just updated today and southeastern sliver of the province is currently at a Level Five for drought. If river levels are already very low, it means they are less likely to push up into extreme high flows. The heavy rainfall could be mitigated by basin and groundwater recharge, plus vegetation is looking for that rainfall as well.
"Worst case scenario, which we鈥檙e not seeing right now, is if the snowpack level is still very high and if we just had hot weather for seven to 10 days in the immediate and then this storm came in," Boyd explained.
"It is definitely bad, but it鈥檚 certainly not worst-case scenario. I think [taking precuations] is prudent for anyone who happens to be near a river or creek, and that can be so different if you鈥檙e near a small creek, it really revolves around flash flooding and that can be one thunderstorm in a 20-minute period that can cause extreme rain so it鈥檚 a threat that exists all through the summer."
Boyd said residents should keep an eye on the River Forecast Centre's advisories and warnings, which can be found here:
"This is an event where radar is very important and can give local residents an idea if the rainfall is actually happening or about to happen in a certain area," he explained.
From a safety perspective, the main messaging is to stay clear of rivers and springs, especially once they start to rise.
"Unfortunately I've seen over maybe the last three years or so is that the fatalities we've had have not necessarily been from flood waters, but quite a few of them recently have been from dogs that are not leashed going into the rivers, getting swept away and then owners trying to save those dogs and they actually are passing away," Boyd said. "Often surprisingly the dogs actually find a way out in the end."
He added the challenge with these types of rain events is the forecasters can predict the storm is coming, but they don't always know exactly where the bullseye is going to be, where the most significant flooding can occur.
