Pemberton Valley Dyking District

03/31/2026

Good afternoon,

We were looking at the snowpack today and although it has been a tough year for Whistler, that is not the case north of us. The Tenquille gauge at 1680 meters is reading some interesting numbers. There is over 1 meter more snow than on this date last year. The last time we had a snow pack peak at over 3 meters there was 2022. Squamish river headwaters interestingly has less snow than last year, so the area of high snow pack appears to be fairly concentrated in the Lillooet headwaters.

There is very little snow below 1200 meters due to the rain events we have had, so spring time run off should be fairly normal. It just depends on how fast it decides to come down. Typically the melt starts to ramp up in the first two weeks of May.

03/20/2026

Good afternoon,

Well, we got that heavy rain this morning that was forecast. I was hoping the weather people were wrong.

By this morning every ditch and canal was overfull and there were several people with water issues on their properties. One thing to remember is, if you have a culvert on your driveway access to your house it is your job to make sure it is clear. These caused several issues today.

The Arn Canal is overbank full and will take several days to a week to drain out. Most ditches in the town area drain into the Arn, so they will take a while as well. Pemberton Creek is dropping quickly now, so that will help with the Arn drainage.

All of the rivers have now peaked and are trending down.

We are now going for a nap.

Send a message to learn more

03/20/2026

Good Evening,

The latest weather update is.

We have another 50mm or so of rain to come. The heaviest rainfall is going to be in the early morning tomorrow peaking at 3-5mm per hour around 6 am.

All of the rivers except for the Lillooet river are stalled out or dropping. The alpine temps are favorable and it is snowing above 1700 meters. We do not think that the freezing levels are going to bump up as high during this next rain event.

The Green river peaked today at 236 CMS, but is likely to peak at over 300 CMS tomorrow (still not in danger territory) We think the Lillooet will peak tomorrow around 400 CMS. Today is the first day of this storm where the Lillooet was higher than the Green. Pemberton creek is likely going to get higher in the morning hours as well and likely higher than it was today.

We have two pumps at Pioneer Junction and we were doing some preliminary pumping today. With Pemberton Creek dropping the culverts are flowing again, so there is no need to keep them running until early tomorrow morning if the creek comes up again. I will be out early to start them if required. I am going to fuel them one last time tonight and when they run out, that is ok.

The Arn Canal is actually dropping downstream of the railroad tracks although upstream areas along Collins road will see high water for some time yet, while the flow works its way through the system.

One more rainy night then some nicer weather this weekend. There is another storm front coming in for Tuesday or Wednesday but it is not near as strong and will only be a 12 or so hour event.

Have a good night.

03/19/2026

Dearest Gentle Reader,

There is a lot to go through so please bear with us.

The River Forecast Center has put out a flood watch for Pemberton. We have spent a lot of time this afternoon looking at the current conditions and the forecast. The "flood watch" has put the PVDD in a very tough situation. Weather is weather and things change quickly. So like always we will show you our data and how we are making our decisions. Today we received 10mm at the Airport and 18mm at the Tenquille gauge (less than forecast amounts). It is currently 2.0C at Tenquille (and cooling, it was 2.6C when I started writing this) and 0C at Whistler peak (and snowing). The rivers are still quite low. The Lillooet is at 115 CMS and becomes and issue at 750 CMS. The Green is at 128 CMS and becomes and issue at 500 CMS. Pemberton Creek is at 10 CMS and becomes and issue at 40 CMS. The Arn Canal has another 1.5 meters it can rise before we have major issues. The areas along Collins road will have wet yards and a few properties may have water issues in the next 36-48 hours, but no flooding at this time. (See Tenquille forecast and Lillooet forecast below)

So by the local data that we have, it looks like we have a fair amount of room for water. That being said the fastest the Lillooet has gone from its current level to 750 CMS is 12-14 hours. The Green can do it in 10 hours. The rate they are currently rising is not reflective of that.

It is extremely difficult to forecast river flows when we have unknown rainfall forecasts and wide elevation variations in freezing level forecasts. If the freezing levels stay at 2000 meters or below we should be good, if they go to 3000 meters things may get interesting. Putting out alerts at this time would seem crazy to some people and yet others would feel safer for it. How do we cover off everyone's opinions and keep people happy? That is difficult.

At this time we think that monitoring the weather and river levels overnight is the best path foreword. Given that we have built a robust monitoring system like we have, we have can monitor the situation as progresses and keep people informed. The areas impacted by the Arn Canal, Airport Road and properties towards Lillooet lake are impacted at the lowest river levels. One Mile lake higher by morning. So please monitor your situation and look for updates through the night. We will be up watching and will have time to alert if we see anything changing. Keep your phone on and sign up for VOP and SLRD alerts if you have not.

Updates as required overnight and we will update in the am regardless to show the situation at that time.

Thanks for your time and understanding of these tricky situations.

Have a good night.

03/17/2026

Good Afternoon,

The weather update today is a good one. The temperatures in the alpine at the Lillooet headwaters have stayed below forecast. The amount of rain in the forecast has been reduced. The River forecast is now for flows like we see every May.

Tomorrow is another day and weather does change, but for now we are looking good. The temps in the alpine will likely drop quickly starting Friday and Whistler has snow in the forecast for the weekend.

Enjoy your evening

Send a message to learn more

03/16/2026

Good Afternoon Pemberton,

I am sure that most people are aware that we have weather system coming in. It is a textbook Atmospheric River. The good thing is that it is forecast to miss us to the North. We will be getting the edge of the storm. It is a bit to early to call what we are going to see here later in the week. Current forecasts are for the heaviest rain to be Wednesday night into Thursday morning.

It is currently 0 degrees at 1680 meters and falling. Freezing levels are looking to be below 2000 meters in the Lillooet headwaters, although Whistler is going to be much higher for Wednesday and Thursday.

The rivers are forecast to hit some decent flows on Thursday, but nothing that causes for concern at this time.

We will do another update tomorrow around noon, after we get the latest weather models.

Have a good night.

02/04/2026

Happy Wednesday,

It is the time of year when the PVDD is reviewing all of our past works and looking forward to 2026 plans. We just received the 2025 Sediment Management report. This report looks at the ongoing sediment influx from the the Lillooet River. We have been monitoring this intensively since the 2010 Capricorn landslide.

There are some interesting findings from this years report. The total sediment load coming down the river has been lower in the last few years, as the total water volume flowing down the river has been lower. This is due to lower snowpacks and low precipitation amounts during high flow months. See graphic below. We do not expect this trend to continue, however is has been a good reprieve from the high flows we saw in 2016 and 2021.

This year we will be doing sediment removals starting in early March. In the past we have focused on 5 locations. This year at the recommendation of our hydraulic engineering consultant, we will be removing at only 3 locations. In the map below we will be only removing at Voyageur, Beem and Big Sky bars. We track the water surface elevations (WSE) at these locations, with level loggers. The past 5 years of data shows us the mean WSE trend at each location. We have observed that the mean WSE at Airport Bar is not changing. So that means that the flood risk to the Areas near that location (Airport and sections of Mt. Currie) are not increasing for a given flow rate (800-850 CMS). However areas upstream seem to be increasing (.2 meters since 2010) We will continue to monitor and have another river survey scheduled in a few years to confirm our data. We monitor our works very closely to ensure that they are not having unintended consequences on fish habitat or transferring flood risk to other areas. .

Enjoy the not very wintery weather!

01/26/2026

Happy January Pemberton,

It has been a bit of a weather roller coaster. The snow pack up high is substantially greater than last year, however there is very little snow below 1000 - 1200 meters. We typically build snowpack until the end of March, but we will have to wait and see. See below graphic of snow depth at the Tenquille Gauge.

This year the PVDD is working with SFU and UBC to continue to monitor the upper Lillooet river and Meager slide. We are also updating our flood modelling to ensure that our data is relevant to the changing river conditions. There is one area that has seen some very interesting changes since 2015. See the graphic below. This section of river has completely changed course and a large amount of trees and riverbank have disappeared from the channels right bank. This is part of a rivers natural process, but changes of this magnitude do alter our rivers models accuracy.

Enjoy the sun before we change back to warmer wetter weather in the coming days.

12/16/2025

Good day,

There are a few areas that are still experiencing water issues. The Arn Canal is the biggest culprit and it will likely be into the weekend before things drain out.

We thought a recap of the event would help see how the PVDD and its partners had to work through this one.

On Saturday we got a weather and river forecast that was concerning. We did our review and met with ECCC and the RFC to go over details. In the Saturday forecast below, The Lillooet was forecast to get to flood state. But being 3 days out from the storm there is much uncertainty. We also know that the River Forecast Centers models are only a guideline as rivers are extremely hard to predict. So we decided to wait for the Sunday forecast to help form our decision making. In the Sunday forecast, both the Lillooet and the Green rivers were forecast to possibly go even higher. However the timing of the storm was still a bit unclear and the forecast uncertainty was high.

We notified the most at risk areas, that had the highest risk of a high water event. This was predominantly the Airport road area, as even if we reached 75% of the forecast flows they would be impacted.

We then made the decision to wait for the weather outlook from our local data on Monday and see if what we were seeing was close to the forecast. On Monday morning (4 am) we could see that even with the large amount of rain we received from midnight onwards, that the rivers were not reacting in an alarming manner. The freezing levels were lower than forecast and the flows from the upper Lillooet were very low. It was not raining in the headwaters.

We then monitored the event as it was developing to see if the rate of river rise was enough to merit an escalation of the flood risk warning. Thankfully due to the forecasting system that the PVDD has developed we have many local data points (see graphic below for map of data points) for monitoring in real time rainfall, temperature and river flows at many points even outside of our drainage area. Weather typically comes in from the coast so we can watch the Squamish and Whistler rivers for an early indicator of what's coming . So we can essentially watch how the weather system is developing and through radar see how the heavy rain areas are situated in the Lillooet watershed.

It is due to this system that we have been developing for 5 years, that we can make the best decision possible for the safety of Pemberton. This system also reduces the risk of unneeded alerts and evacuations. So if at some point in the future we say that you need to leave it is not a decision made lightly. It has taken a lot of hard work to find funding as well as augment with PVDD funds to make this a reality. We hope to add another weather station at the Birkenhead river headwaters next fall as we have inadequate data for that area.

Thanks to all the effort put out over the last few days from the SLRD, VOP and Lil'wat to get through another high flow event.

Have a good day

12/15/2025

Good afternoon,

The good news is that all of the rivers are trending down, however with each new rain shower it just slows the rate of drop.

We did end up having to do some pumping in a few locations to keep what we could under control. The freezing levels are dropping fast and it may get down close to zero overnight.

The persistent issue we will see over the next few days is the slow draining of the Arn Canal. Once Pemberton Creek drops this evening it will speed that up, but we think it will be a few days before all of the water finds its way out.

The area upstream of the CN tracks is still holding a lot of water so Collins and Urdal area will not see the ditches and properties drain for next few days as there is still a large amount of water from the Arn Canal and 2 Mile Creek draining in.

Maybe snow Wednesday / Thursday?

Have a good night.

Send a message to learn more

12/15/2025

Good morning,

It was a very rainy night. 24 hr rain at Tenquille was 52 mm and the Airport received 47.5 mm. Freezing levels are sitting at about 1800 - 2000 meters, which is way better than 2500 meters, which was forecast.

The two rivers that are really ramping up are the Green and Pemberton Creek. The Green is at a 2 yr RTP at 260 CMS and Pemberton Creek is at 2 yr heading to a 5-10 RTP in the next few hours. It is currently at 20 CMS. Pemberton Creek is making the Arn drainage problem worse at the Arn is a tributary of Pemberton Creek. So the creek is currently backing up the Arn.

So far the Lillooet is cooperating well and the inflows at the headwaters are still less than we see during freshet. However if this starts to ramp up quickly things will evolve rapidly. We are watching this closely.

The famous puddle is forming on Vine road. Please use common sense and don't have you and your car become this years Christmas meme. Drive around it.

We will update as things progress this morning.

It's "bring a poncho" to work day today.