Alberta FLOOD Outlook - May 28, 2026

Añadido: 2026-06-04

[00:00:00]Well, rivers are running high out there across parts of southern Alberta following several days of heat. This is the Elbow River near the Mloud Trail Bridge uh near downtown Calgary. We can see some minor flooding there along the river pathway. Let's get straight into it here. Disclaimer right off the bat. I am not a hydraologist. I'm a weather forecaster. So, we're going to be talking about how weather could be influencing flood risk in the coming days in southern Alberta given that we have a significant rainfall event on tap. So, let's start out by looking at this map from rivers.alalberta.ca.

[00:00:28]We can see flood watches along the Pipstone River and the Bow River near Lake Louise and downstream through the Bow Valley, BA, Canmore into the Ghost Lake. We've got a high stream flow advisory. Already seeing some minor flooding there along the Bow in B.

[00:00:43]That's largely because of the heat here in recent days and they had a significant snow pack there in the mountains this past winter. And uh you know, looking at our May snow survey results, that snow pack still lingering there uh into the beginning part of May.

[00:00:56]We can see most of that snow through the winter. It was as soon as you get north of the crow's nest pass uh through Canonasca's BA and into Jasper National Parks well above normal snow pack in this region here. So this is playing a role here but significant kind of a gradient here in southern Alberta night and day difference. You get down into Waterton southward into the Milk River Basin down into Montana there. Uh much below normal snowpack this winter. They had a very dry winter abysmal snow pack in the western United States there. the the gradient here kind of where that those storm tracks um the storm systems were really kind of following along this track here in the winter and totally avoided this area further to the south.

[00:01:35]So that's the reason why we see that significant discrepancy and that's playing a big role uh downstream. You know we look at our water supply outlook for those same river basins this summer.

[00:01:45]The result you can see uh you know much above normal flows expected through this summer in the Bow River uh watershed here. You can see as well above normal through much of the north Saskatchewan, the Red Deer, uh, parts of, you know, the sheep and the old man here. This is, you know, good water coming out of the mountains here. But you get down here completely different into the Milk River Basin. Again, this is our only Canadian River basin that ultimately flows into the Mississippi River and out into the Gulf of Mexico. Uh, very very dry down here. In fact, so dry that irrigators are not allowed since April 30th to draw water uh from the Milk River. So, that's a a little bit of a tense situation down there. We'll see how that might change in the coming days with substantial precipitation possible in this region.

[00:02:27]Uh, but you can just see how dry it is down there. Multi-year drought, four, or fiveyear drought down in far southern Alberta. People's dugouts and ponds completely drying out down there for the first time uh that many people have observed. So, we can see again this is going to be playing a big role in that runoff in the coming days here. And the reason why we're seeing such substantial melt all of a sudden, I mean, it is fairly typical for spring, but you we went from like a a cool spring, lots of snow suddenly to this warmth at the uh the end of May here. So, we're seeing this kind of transition into the spring fresh period a little bit early, and it's it's really off to the races. This is what's called a meteoroggram here.

[00:03:04]It's basically just a temperature trace that we're seeing uh at the Nikisa Ridgetop weather station over the past week or so. And we can see temperatures really since May 22nd have not dropped below freezing. And this station exists at 2543 m above sea level. That's up there uh at the top of one of our most famous ski resorts here in southern Alberta. Temperatures have been warm and uh you know we also have some relatively high humidity. So that's really going to be efficient for melting the snow in the alpine. So you can see very very warm conditions in the alpine playing a significant role in that rapid melt. If we actually go ahead and look at our uh snow pillows in some of our spots here, this is um Little Elbow Summit in the Elbow River headarters southwest of Calgary. We can see uh we've been seeing that rapid melt uh really since the beginning of May. It started with those warming temperatures, but really taking off in the last couple of days here with this warmth here. Uh we can actually go ahead and we'll take a look at two more stations. Let's go up to Sunshine Village here. Very substantial snow pack this winter. last week or so significant melt and again that's uh kind of melting into that Bow River wershed and we'll look at one more station here the Skoi uh near Lake Louise and we can really get an idea for why there's a flood watch in that area just precipitous decline here and what this is showing is snow water equivalent that's basically the amount of water that's stored in the snowpack. So if you were to melt it all all at once this is the level of water that you would have. So, I mean, and we're looking at uh the the snow pillow here southwest of Calgary. Still 400 mm of water stored in that snow pack at that snow station. So, I mean, there's still a lot of snow out there to melt, a lot of water to run off into our river.

[00:04:45]So, this is going to be a consideration in the coming days. If we actually go ahead and look at some of our hydrographs and just see what the river flows are like, uh, Lake Louise here, we can see, uh, we're well above normal flows and our water levels are high and they continue to climb. And we're expecting, you know, it could rise.

[00:05:01]We're we're being told the rivers could rise here in in the BA area, another foot through Friday as temperatures continue to be warm. Looking at the hydrograph there in B where we're seeing some minor flooding along the river.

[00:05:11]Again, uh, well above normal flows and water level there. and we'll take it down here into the Calgary region.

[00:05:17]Looking uh at Bragg Creek's hydrograph as well, running on the high end of average, but look at this spike here.

[00:05:24]There were some nearly stationary thunderstorms out in Canonasis country yesterday afternoon. So, I would imagine that's likely the reason we're seeing this significant sudden spike here in those river flows. And you go downstream into Calgary to Sarsc River uh bridge here, we can see uh we saw that spike about 6 hours later, 6 hours downstream of Brag Creek. still on the high end of average there flowing into the dam. But you get downstream of the dam here uh into uh you know near Sandy Beach I think here along the Elba River in Calgary. Uh again this is a controlled flow that's why you see these steps here uh but running above normal here as it looks like officials are releasing water at the dam to make room for that big influx of water coming in from the mountains. Let's take a look at the weather picture here. And if you saw my last YouTube video, you'll you'll you know, we talked about the omega block pattern here in North America. Uh notice down here in the southwestern states.

[00:06:17]Now, we're going to start here Friday morning. This is midnight tonight. Uh Friday morning, this upper level low.

[00:06:23]This is going to be ultimately the big weather player in the coming days. Uh but we're seeing this omega block pattern here shaped like the Greek letter omega. This is the jetream in the middle part of the atmosphere about 5 km above the Earth's surface. this little you know this upper low is just slowly meandering its way through the western states and by Sunday starts to approach our region. It is moving very very slowly. Uh again that blocking pattern continues to keep it kind of near stationary for uh 2 to three days and uh that is the reason why we're seeing such substantial precipitation totals forecast in our region. It just kind of parks and hangs out there uh resulting in a lot of precipitation. And this event is really going to begin uh late Saturday. So this is late Saturday here.

[00:07:07]Rain starting to spread into our region and persisting through Sunday and Monday and Tuesday before it starts to taper off. That folks is a long duration precipitation event. And one of the reasons why we're uh seeing the potential for some substantial precipitation totals as moderate to heavy rain persists for quite a while.

[00:07:26]We're looking at our ensemble forecasts here from uh the European and the Canadian here. And when we start to see agreement among model ensembles, we start to gain uh increased confidence in uh the timing and the positioning of where the heaviest precipitation is going to be as well as how heavy that may be. Precipitation uh does to be one tend to be one of the hardest variables to forecast for weather models, but we're seeing some pretty good agreement here. Looks like portions of northern Montana, far southeastern BC, uh, but especially southern and central Alberta, substantial totals likely 50 to 75 millimeters over a large area of Alberta with this storm system. Locally enhanced totals in far southwestern Alberta, kind of hinting at those uh southwestern foothills where we may be seeing some uh UPS slope effect enhancing those precipitation totals. Uh, looking again here at another map from Cood. This is Alberta and we can see our uh surface low pressure system really starts to build and and kind of hangs out there in the southeast corner of Alberta, southwestern Saskatchewan for quite a while before it moves on out. Uh in behind that, you're going to be feeling very very different weather conditions than we've been experiencing with these hot, sweaty conditions. It's going to be cold, very windy, and uh very wet as this storm system really uh kind of starts to get going through the late part of the weekend and into early next week. Uh and we're going to be seeing several what are called lifting mechanisms. Different ways that we're seeing rising air through the atmosphere uh contributing to the kind of the magnitude and the intensity of the precipitation of this storm system. This low pressure system hanging out here.

[00:08:58]These are winds at about 700 millibars.

[00:09:00]Again, about 3,000 mters above sea level. Kind of the highest uh the the height of the highest peaks of the Rockies west of Calgary. We can see a lot of that wind just piling into the terrain. That's what we call UPS slope flow. There are several different types of lifting mechanisms ongoing, but that is going to be one of the most important ones here. As you force that air up the slope of the land, it really can enhance your precipitation totals, and that's likely why we're seeing those uh really enhanced totals likely along the terrain in portions of southwestern Alberta before that system uh moves its way out.

[00:09:33]And again, we can see just with this kind of topographical map of Alberta or this this terrainbased map here of Alberta and our river basins. Again, Bow River Basin here, Old Man Milk and uh Red Deer, these ones are going to be probably receiving the most precipitation from this event. But again, uh high, you know, high terrain here. These peaks rise upwards of 3,000 meters. And when you get that, uh, you know, that flow flowing up the slope of the land, it's just like hitting a wall and it's forced upward. uh numerical study actually from the 2013 floods uh indicated that 50% of that precipitation total uh was the result of the mountains here. So, you know, in other words, had the mountains not been there, you would have only received about half the amount of precipitation we saw uh from that storm system there. And uh so, and taking a look at some potential buffers working in our favor here. There's a couple pluses and there's a couple minuses. So, we'll talk about these here. Looking at drought across the landscape here. We're seeing uh severe to extreme drought locally here in uh northern Montana and then getting into southern Alberta. Like I say, that's a multi-year drought there in southern Alberta, particularly down there in the Milk River watershed. We've also got this pocket of persistent stubborn drought sort of in the Red Deer Silven Lake Rocky Mountainhouse area. Um so soils are dry out there and it's we've been really dry actually. If you look at our percent of average precipitation for the past 30 days, less than 40% of normal, very dry May. So, actually, you know, with this storm system, pretty significant rainfall totals, but, you know, it's actually just bringing many locations up to near average or maybe slightly above average for their May totals. Um, but very dry out there. So, that may act as a buffer initially, uh, you know, allowing that water to infiltrate into the soil being largely beneficial for a lot of agricultural producers. Of course, uh you know, most of southern Alberta now the planting is complete. You get into central Alberta, I believe we're getting close to completion there as well, especially and hopefully with these warm temperatures, most folks have seed in the ground by now. Uh but uh you know, looking at our soil moisture, percent of normal soil moisture here, again, it's getting dry out there in southern Alberta. And again, there's that pocket of dry here in central Alberta between Calgary and Edmonton. The problem with that though is with this long duration event is eventually you're going to lose that capacity for infiltration. You're going to start seeing more runoff as the soils become saturated. So that's one thing that we're going to have to watch.

[00:11:55]Initially have a little bit of a buffer, but over time as the soils become saturated, especially given the long duration nature of this system, if we're seeing heavy rains after 3 days, most of that's going to be running off into our rivers and streams, perhaps pooling and ponding into low-lying areas. Another potential buffer here uh is the uh the the freezing level is going to be kind of near or just below the mountaintop level out there. So again, beginning into Sunday and into Monday, there's your freezing level at uh at 700 millibars. Looks like most of the mountains are going to be uh below freezing, just below freezing there. So likely a lot of that that precipitation is actually going to fall as snow at least in the upper reaches of the mountains in the high alpine there. uh likely mids slope and down still going to be a cold rain but in the upper elevations that's certainly going to help. Uh you know it's not the same as the 2013 situation for instance where you had warm rain falling on snow right up to the tops of the peaks. In this case uh you know we see a little bit more of that slowrelease water as a result of snow falling up in the alpine there. Uh as we can see here our Canadian and European ensemble showing some snowfall here but again this is in the main ranges. uh likely going to be seeing snow up in the alpine, but out in the the kind of the eastern slopes, still likely mostly rain. Granted, where there's less snow to melt, but certainly a consideration there. Uh let's look at our freezing level. This is a kind of a confusing image to look at initially, but this is at B. And what you're looking at is basically the station elevation down here. BM sits just below,400 meters above sea level and goes up to about 3,000 here. And we can see right now, again, super warm. This is Friday and Saturday. uh you know we're getting up to about you know 10 degrees Celsius near the height of most of the peaks around B. They would be mostly in this area right here. And so as you see you know we get into the heart of that storm system on Monday.

[00:13:45]Our freezing levels drop down here uh into about 750 millibars. So you know 2,500 meters. Uh so the highest parts of the peak certainly going to be picking up snow through the heart of that that storm event which will certainly help.

[00:14:01]But again, a lot of that rain is still going to be falling mids slope and downwards. Um, so still uh somewhat concerning there. So again, uh we're going to see freezing levels come down.

[00:14:12]Certainly not a 2013 type situation where it's really warm all the way up to the peaks of the mountains, but um you know, this is still um somewhat of a buffer, but we'll see how it actually ends up playing out. Uh so again, we've got pluses and minuses uh with this storm system. Again, the prolonged rains uh can actually make the soils become saturated. The other problem is that uh rivers are quite full right now. So, they're not going to have much capacity to uh take in much more runoff and we will be seeing more runoff uh both from some snow melt but also uh just from the sheer amount of precipitation entering these river basins uh with this largecale rain. So with, you know, some totals, some models indicating some totals could exceed 100 millimeters locally over 2 to 3 days, that's a substantial amount of water. So we're certainly going to be watching for some flood potential out there in southern Alberta. Again, we're going to have to listen to uh the experts on this and uh follow the advice of local authorities in the coming days and see just how how significant this could play out because again uh weather models can change.

[00:15:13]Weather the weather situation can change, but right now uh we're certainly looking at the potential for some floods in flooding in parts of southern Alberta along our rivers and perhaps even to the east. Again, if we see 100 millimeters in Calgary, unlikely at this point, but if you see that much rain, again, uh that's a lot of water coming down. I wouldn't rule out basement flooding. You know, you got flooding in low-lying areas. Certainly, uh would want to make sure that the downspouts are on and pointing away from your house and not toward your neighbor's basement window.

[00:15:43]Uh this is a lot of water potentially coming. Hopefully more beneficial given the long-term drought out there, but uh but we certainly are entering flood season. Another consideration too is uh you know June is our wetest month and so uh this first event may be more of a primer. We'll see how much flooding we see with this one, but if we see subsequent storms like this one in June, that's where we could start to see some uh more substantial concerns with flooding. Of course, we've had we made some significant improvements out there to our flood infrastructure across southern Alberta since the 2013 flood.

[00:16:15]But nonetheless, something to watch here. Again, uh you know, be prepared.

[00:16:20]Getprepared.ca CA is a great place to start looking for how to prepare for floods. And again, if you're in the city of Calgary, we have our own page here.

[00:16:26]Government of Alberta has their page as well. So, we're going to have to see how this plays out in the coming days, but uh stay tuned. Looks like there could be some flooding potential in southern Alberta given this heavy precipitation that's on tap. Stay tuned. Thanks so much for joining and we'll talk to you next time.