Flood Review

[andrea-lake]

In his April 24th post, seewood asked how do they get the lake any lower, given that the flood gates are already wide open?

I understand your point. To put the issue into perspective, we should ask this question: What should they do in a year where there is a much larger than normal snowpack AND an expectation of a very wet April, May and June? Under this scenario the 1974 rules require them to draw down the lake to a least 40 cm below 341.45 meters, which is where it was last week. In order to build enough storage for snow melt and rain they would need to draw the lake down to 341.05 meters. The only way to achieve this large drawdown is to start significant outflows at the Penticton dam in early March instead of waiting until early April. If they wait until April, as they’ve done this year, then it’s impossible to build the required contingency as you pointed out.

We know there’s a larger than normal snowpack this year, but we don’t know if there’s going to be more than average rain coming. My sample forecast assumes a normal amount of rain this year, so we should be spared a flood from high lake levels as the authorities are telling us. We're still waiting to see an official forecast with error margins based on normal variations in Okanagan weather patterns.

[Jflem1983]

I think the lake is gonna be fine. Rivers and creeks however. Not so much. Wont take much rain to bring down even more hillsides. Overflow more creeks etc. Gonna be a wild ride thru May. Surely by june 15th we are mopping up the flood and starting to declare a new state of emergency. Fire season

[andrea-lake]

Update on Mission Creek forecast

The BC River Forecast Centre official April 25th forecast had predicted peak flows for Mission Creek to hit 60 cubic meters per second by May 1st. The updated forecast as of April 27th shown in the image below reduces the peak flows to 50 m3/s. This should bring some relief to people living along the creek.

The live link to BC River Forecast Centre is here:
http://bcrfc.env.gov.bc.ca/freshet/clever/08NM116.PDF
The forecast is updated regularly so it will change depending on when you download the link. Remember there's a fairly wide error margin in these forecasts.

[swamp1967]

Mission Creek is up of course (keep the updates going Andrea-Lake) tonight. As predicted, at the KLO - Mission Creek Bridge, debris is getting trapped because the Ministry of Forests, etc didn't remove gravel under the bridge. See how long this lasts.

[Glacier]

Coldstream Creek is now higher than it was all last year! Big time flooding in Coldstream right now! There's a field with bulls in it, and half of it is under water.

[andrea-lake]

As previously noted, the BC River Forecast Centre updates their forecast regularly for Mission Creek. In the latest update below, it looks like the flows are peaking tomorrow instead of early next week; and the peak is back up to 60 m3/s from the 50 m3/s peak they were forecasting yesterday. Castanet posted a good picture of Mission Creek, showing how high the water rises at this flow rate. (See following link):
https://www.castanet.net/edition/news-s ... htm#224932

[Fancy]

So far so good though with lake levels

[normaM]

Bellevue is running fast and furious.. not too high tho.

[Glacier]

They are cutting back on the stream flow out of Okanagan lake. Flow rates have tanked since April...

[featfan]

Looking for hard working people to fill and place sandbags for the next couple weeks. $20.00 per hour 7 am to 3:30 pm Monday to Friday. call 250-765-3702 and ask for Keith

[andrea-lake]

Mission Creek flows are forecast to hit their highest levels this year at almost 80 m3/sec on May 8th.

See post above for help with sandbagging.

[andrea-lake]

Perhaps someone attending the Flood Outlook briefing on Thursday by Emergency Management BC and the Regional District: https://www.castanet.net/edition/news-s ... htm#225276
could print-out my sample forecast below and ask if they could make an official forecast of the lake levels along with their best estimate of the high and low error margins.

Last year they had to revise the forecast lake level twice based on changing circumstances. We all recognize the uncertainty around the inputs to their model, however, people still need a realistic forecast of how high the lake might rise along with a worst case scenario so that they can plan accordingly. This year we've not seen their forecasts at all.

[featfan]

Mission Creek flows are forecast to hit their highest levels this year at almost 80 m3/sec on May 8th.

Mission Creek May 2.png

See post above for help with sandbagging.

Looking for work, but there is no way my body could do sand bagging.
I wish it could.
$20 per hour is a very livable wage for me.

[andrea-lake]

Mission Creek is now forecast to be flowing at very high levels, getting close to 100 m3/sec by May 12th.

[andrea-lake]

The turnaround in lake level is even faster than last year. Image below shows changes in the past month alone:

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