Final Weekend Update 9:30PM – Strong Winds and Rain down trees whip up sail past. River flows continue to rise. A break Monday.
The rain began in earnest this afternoon and didn’t let up. The winds came too this time! Our strongest gust was 68kph at 7:40PM.
We have received another 32mm today with most of that falling this afternoon. The rain will be under-reported because of the wind blowing it over the gauge but it usually isn’t more than a few millimetres out.
The total for the rain storm since Friday is 108mm so far. Despite the wind the strongest rain rate we achieved was this evening at 7:20PM of 13mm/hr.
Right in the middle of all that, there was a sail past! It was a little crazy down at Harbour Quay!
UWash predicts another 8mm to fall between 10PM and 1AM and another 4mm to fall between 1AM and 4AM. That should give us around 50mm total for the 4AM-4AM period, which is on target for the ‘up-to 60mm’ predicted this morning.
The forecast for Monday has actually got both wetter and less wet… as it is now slated to rain from around 11AM to 4PM but it should remain fairly light and “only” get up to 16mm in the 4-4AM Mon/Tues period.(30mm in higher elevations). Lets hope that ‘light’ doesn’t surprise.
The next big wave will come late Monday night/Early Tuesday morning. (Starting around 2AM). It will peak around 10AM, just after high tide and clear out by 3PM while it moves south… it will then whip back to the north near 4AM Wednesday.
Total Accumulation Tues/Wednesday 4AM-4AM. Upper limit 60mm though edging on the lower side and depending very much on timing and how far south the rain band actually slips. 
Here is some good news. There is only up to 60mm now forecast in the 72hrs between 4AM Monday and Thursday… though double that in the higher elevations and very dependant on timing and exact position of the flow.
That is the furthest out I’ll go as that is the most reliable. The long range UWash forecast though has just 30mm falling in the 72hrs between Thursday and next Saturday but we should stay on our toes as these forecasts have been changing often and missing their marks though UWash continues to have been the most accurate.
On the ground water side of things… both the Sproat and Ash river flow gauges are continuing to slowly rise at this time.
Ash River is below
(December 2014 storm max was
3.6m[greem] and 310m3/s[orange])
Sproat
(2014 storm max was 4.5m and 300m3/s)
We are about half way in terms of flow amount into the Somass compared to last year which were, possibly, the most intense 4 days of rain on record for Port Alberni.
Stay Safe out there everyone. And one last note. Tseshaht First Nation has declared a State of Emergency as they already have some homes with water encroaching on the property. They are trying to be proactive this year to get ahead of any potential flood waters. If you can donate your time and energy Monday, they will be filling sandbags at the Tseshaht Admin office off of Highway 4 beside the “Orange Bridge” starting at 9AM. They will be ringing vulnerable homes with sandbags in preparation for the expected rains, and further increase in river flows on Tuesday.
This will be the final update for this post. I will have a new post probably Monday afternoon or Monday evening depending on how the next storm looks.
Updated 1:30PM – River Forecast Centre downgrades flood watch to high streamflow advisory but still on guard for next storms.
At noon today the BCRFC downgraded the flood watch for the Somass basin to a High Streamflow advisory. This is good news at least temporarily. However they do say they are keeping an eye on the situation as the next storms roll in. Here is their current statement.
High Streamflow Advisory Maintained: Somass River
Downgraded from Flood Watch: December 6, 2015 12:10pm
The BC River Forecast Centre is downgrading the Flood Watch to a High Streamflow Advisory for:Somass River basin including the Ash River and Sproat River and smaller streams in the surrounding area
High Streamflow Advisory Ended: East Vancouver Island
December 6, 2015 12:10pm
The BC River Forecast Centre is ending the High Streamflow Advisory for:East Vancouver Island including the Tsolum River and Browns River near Courtenay, and the Englishman River and smaller streams in the surrounding areas
The 24 hour total rainfall, ranging from 50 mm to 150 mm, has been recorded over southwest Vancouver Island including Port Alberni and the Somass River watershed. The Somass River including the Ash and Sproat Rivers have responded to the rainfall and are still rising slightly or leveling off. Environment Canada forecasts less than 50 mm for the rest of today into Monday, and as such, dramatic rises are not expected in these rivers for the rest of today and into Monday. However, Environment Canada forecasts a 24-hour rainfall ranging from 40 mm to 70 mm from Tuesday to Thursday. Additional rises of river levels are therefore expected from Tuesday night. Depending on the amount of rainfall and how much the rivers recede between now and Tuesday will determine the risk of flooding from the forecast Tuesday storm.The 24-hour total rainfall of approximately 50 mm to 80 mm has occurred on the east side of Vancouver Island, with rainfall easing this morning. Environment Canada forecasts about 10 mm for the rest of today into Monday. The rivers on the east side of Vancouver Island including the Tsolum River, the Browns River and the Englishman River are receding but minor fluctuations are expected the rest of today and into Monday but are forecast to be below levels of concern.
In the current situation, the public is advised to use caution around rivers and adjacent low-lying areas.
Another storm is forecast to cross the south coast on Tuesday with rising freezing levels. The River Forecast Centre will continue to monitor conditions and will provide updates as conditions warrant.
Updated 10AM Sunday – Morning Models Update and Accumulations to Wednesday (up to 100mm or more)
The latest UWash models are out. I’ll also compare to the current Canadian and US Models.
UWash continues to say 60mm between Sun/Mon 4AM. You can see the progression of the forecasts for this time here. They have diminished over time but so did the progressions for the Saturday event and the last one overshot that diminishing and we ended up with slightly more than the last model run.
Heaviest rains today are predicted around 5-6PM with a final shot around 9PM. It should clear after midnight though there will be showers all night.
Monday will be mostly dry though there is a blob of rain forecast to come through mid-morning. Lets hope it moves through quickly as forecast and allows river levels to subside before the next wave.
The next big storm will start late Monday night/early Tuesday morning and last until afternoon Tuesday. Accumulation between Monday 4PM (Afternoon) and Tuesday 4PM are for another 60mm.
There is a lot of uncertainty about what happens after Tuesday as the ‘firehose’ whips around to the south and back north so I won’t go into those forecasts.
However lets look at the other models as displayed at SpotWX.com.
The following are accumulations for Sunday:
The High Resolution/Short Term Canadian Model (LAM) (from last nights run, not updated yet today) says 45mm for Sunday.
The larger level Canadian GEM model (run this morning) says only 35mm for Sunday.
The US HRRR model (this morning) says less than 25mm.
The US GFS Model says 35mm
So the University of Washington seems to be the outlier with up to 60mm falling in the period these other models say half that.
Finally, lets look at the accumulation between Sunday 4AM and Wednesday 4AM (72 hours).
UWash is firmly into the 2.5-5in (60-130mm) range
Canadian Ensemble (combination) Model Average: 118mm (Notice the tight shaded areas which indicates good agreement in the many models it uses. Ranges are 103-125mm and 84-150mm.
The US GFS says 87mm.
The three big time models are in good agreement.
The Good News is there is that gap on Monday. So I am hopeful that there will not be too huge an input into the rivers. However, there is already flooding and this certainly has more ability to add than subtract. There does look to be a break after Wednesday until the weekend. Maybe. lol. I’ll keep you posted!
Update 8AM – Noting River Levels
Short update. We haven’t had a long enough pause (need 3 hours) in rainfall to reset the Rain Storm gauge on the webpage. So we are at 83mm and counting. Nice.
I have added links under the “Reports and Links” section of the menu under “Fire and Water” that include the river gauges on Sproat and Ash (which feeds Stamp) River.
Here is what they look like now… Sproat is still filling but Ash has peaked for now:
Sproat River
Ash River
To put those in context here is the same graph stretching all the way to last november so we can see the big flood event last December 1st.
Ash
Sproat
So we are definitely not to the same threat as we were last year… but we are building to there and have a long week to go.
Update 10:30PM – Sunday Rain Coming 60mm more by Monday 4AM.
So:
https://twitter.com/alberniweather/status/673377018889682945
OK so it is still raining a little bit but not much. The worst is over for now.
I went down to 3rd Avenue and Dry Creek to see how it was at high tide. From my eyeball it was no more than 1.5ft higher at 8:30PM as it was near low tide around 2PM (pics in previous update).
And most importantly, it was flowing quickly under the trestle and out toward the Inlet. That may not have been the case if it was a King 12ft Tide.
So what happens next? More Rain. It will begin again early tomorrow morning but won’t get intense until Monday afternoon (2ish) especially around 5-7PM. It should taper off by midnight Monday.
Accumulation has us in the “pink” again… up to 60mm.
We should get a bit of a longer break on Monday before a similar system hits on Tuesday. Then more on Wednesday then Thursday.. then… you get the idea.
There is light at the end of the tunnel.. but you’ll have to wait a week!
Hang in there folks! I’ll try to have another post Sunday especially if the River Forecast centre or EC update anything important.
Updated 7:30PM Saturday – Models underestimate – Flooding on 3rd/4th begins – rain to continue to midnight.
If you look below you will see the predictions for between 4AM Saturday to Sunday were for up to 60mm. (Pink) We only had 4mm by 4AM this morning at Alberniweather. We are now at 63.75mm and the rain is not supposed to end until well after midnight. So we will blow through that prediction.
Similarly, the supposedly super accurate, short range, HRRR and LAM models this morning predicted less than 30mm to fall between 7AM and now… We have busted through that too.
Stay safe out there. This is only the first storm. The next one will start up after a break Sunday morning. The rivers will remain high though they may come down before they rise again.
Both CIty and Tseshaht offices are in heightened states of readiness and are being updated with the latest information for flooding. Tseshaht has resources available including sandbags at the office. PEople in city limits can get sand and bags from the City works yard parking lot anytime.
Stay safe out there. I will have another update later tonight once the new model runs are out so we can get an idea of what is coming tomorrow.
Here are some pictures I took of the new Dry Creek improvements. It is pretty full but doing well. I am going to go down tonig and tomorrow at high tide to see how it is doing.
Updated 11:15AM – Flood Watch Issued for Somass Basin. Expected low flooding by afternoon.
The Ministry of Environment and Emergency Preparedness BC have issed a Flood Watch due to the copious amounts of rain coming in the next few days. Here it is as released yesterday afternoon. Apologies I did not see it until now. Some low lying areas along the river can expect flooding by later this afternoon. It should recede Monday but the threat may return Tuesday. Stay tuned. There are sandbags and sand available at the City Works yard if you need some. Tseshaht reserve is also on high alert given what happened last year. If you live on reserve contact them for help and information. They will have sandbags as well.
The BC River Forecast Centre has issued a Flood Watch for:
Somass River basin including the Ash River and Sproat River and smaller streams in the surrounding area.
Rainfall totals from 80 to 120 mm were recorded on central Vancouver Island over the last two days. High flows were prevalent along eastern Vancouver Island with localized flooding reported in several locations. A series of robust storms are approaching this weekend and this pattern of storms will continue until next Wednesday. Due to their highly dynamic nature, timing and precipitation totals remain difficult to predict for conditions beyond 48 hours.The next storm will affect Vancouver Island by late Friday night and through the day on Saturday. Forecast rainfall totals range from 80 to 150 mm through to Sunday morning with higher totals along the west coast and central inland headwaters of Vancouver Island. Further details on the storm track and timing are available at the Environment Canada weather blog.
High streamflows are expected in the Somass River basin including the Ash River and Sproat River. Low-lying areas may experience flooding by Saturday afternoon as flows exceed the 2-year return period flow. Based on current forecast conditions, flooding on the Somass River is expected to be more widespread by Sunday if rainfall persists through Saturday night.
High Streamflow Advisories have also been issued for:
East Vancouver Island including the Tsolum River and Browns River near Courtenay, and the Englishman River and smaller streams in the surrounding areas
Along eastern Vancouver Island, streamflows are expected to exceed the 2-year return period flow in major systems by late Saturday and through Sunday. Streamflows on Vancouver Island are forecast to recede by Monday morning ahead of another storm on Tuesday.The BC Storm Surge Forecasting Program is indicating a moderate risk of coastal flooding over the weekend at the forecast location in Campbell River. High tides, similar to Thursday’s conditions, are expected around mid-day on Saturday. Details of storm surge forecasts are provided at the B.C. Storm Surge website.
The public is cautioned to stay clear of rivers due to quickly flowing water and potentially unstable riverbanks.
The River Forecast Centre will continue to monitor conditions and provide updates as conditions warrant.
Updated 8:30AM Saturday.
It is raining pretty good out there but the super high resolution short term forecasts agree with UWash that accumulation will not be too bad. Only another 20mm is expected to fall by 7PM or so tonight in addition to what has fallen so far. The strongest wind will now come in the evening but only 20-30kph if the American High Resolution Rapid Response is to be believed.
Sunday afternoon is still predicted to give us 60mm of rain starting around 3PM. Similar wind as today.
……Last Nights original Post…..
The rain has started again and its not going to stop much in the next few days. The good news is, the forecast has backed off a bit for Saturday.
Our region has not backed off from up to 100mm in 24 hours between Sat/Sun 4AM to up to 60mm and possibly less.
Similarly, the wind threat has backed off as well though it will still be strong gusts on the outer coasts and east side and Juan de Fuca.
That said, as we saw on Thursday, forecasts can change at the last minute so be prepared.
As the Special Weather Statement says, Saturday is only the beginning. After a short break Sunday morning, the next system will roll through. It has now taken the mantle of being the big bad storm so we will see just how bad.
The model currently has us, again, in the up to 100mm in 24hrs between Sunday/Monday 4AM.
The wind is stronger than the strong forecasts orginally were for Saturday at least for the West Coast which may include the Valley.
I will leave it there for now.
Stay safe out there. Avoid the rivers and streams as they will be running high and watch for downed trees as the ground saturates depending on if the wind picks up.
If anything major changes with the models Or EC issues a warning for Inland VI, I will of course update. Have a great weekend.
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