Mt. Nusatsum

Mt. Nusatsum

Sunday, September 26, 2010

Flood Update

Well it's been a wild and historic 48 hours in the life of the Bella Coola Valley.  Only a few days ago I was going on about the low water and beautiful condition of the Bella Coola River and now we've seen the Bella Coola deliver one of the most powerful and large floods in recorded history and living memories.  There are many sources of photos in the Facebook world, so I won't post any photos tonight but will cover what I can determine to be reasonably factual.

First the rain - from September 24 Friday morning at 7 AM to approximately 8 PM Saturday September 25, the rainfall recorded in the valley was 245 mm (9.6 inches).  The scale of this flood with 9 inches of rain and no snow to create a rain-on-snow flood event (usually the source of the worst Bella Coola River floods) suggests a massive widespread rainfall.  Piecing together comments on the extent of the rainfall it appears that what made this flood so big, is that the entire watershed of the Bella Coola - all the big tributaries, Salloomt, Nusastsum, Talchako, Atnarko all received a massive amount of rain.  Often these storms are most intensive in the lower valley or one of the tributaries, or sometimes the upper valley and not the lower valley, but this one was widespread.  You have a situation with a watershed of several 1000 sq km covered in 9 inches of water.  The Bella Coola had to burst banks not burst in anyone's memories to handle it.

Damage - Around midnight the east end Airport dike breached and then eroded a hole.  Water was pretty much from one end of the runway to other. It took most of the day to let the water recede and clear debris bus some small aircraft used it this afternoon.  The low area in Hagensborg had record levels of water - from talking to reliable sources it seems like at the deepest,water on Highway 20 through the area around Meechams Garage was in the 4 foot range.    The rock cut area near Bella Coola townsite was flooded for a period.  Grant Road North was well underwater.  Tippee's corner had washouts and water over topping the highway.  At Nusatsum Bridge there was a washout from a small Creek.  On Salloomt Road, the approach to the Mill Creek (creek just before the south end of the Bailey Bridge) was out.  More seriously the south end approach to the Bailey Bridge was almost completely washed out.  The Bridge is still sitting on pilings but the approach is washed out.  People in the Salloomt area still have power, but will be stuck there for awhile. I don't know the status of Salloomt Road beyond there.  In the area around the Glacier View, the river topped the highway, the Noosgulch Forest Service Road bridge at 1 km was washed out and a new channel formed.  In the area of Canoe Crossing, evidence I've seen suggests there was likely 3-4 feet of water over topping the highway.  In Firvale, long time residents had water nearly two feet higher than ever recorded.  I don't have much information above Firvale, no one has been able to drive that far.  There are reports of extensive damage to Highway 20 in the Tweedsmuir Park area.

In the meantime....waiting for another rainstorm forecast for tonight.  Hoping it doesn't contain the amount Environment Canada suggests, as the Bella Coola River was only just starting to get back to it's 'normal' flood level high water stage around 4 PM.  It's still pretty full and can't take too much more until 48 hours of draining time has happened.  Grizzly

2 comments:

  1. Hi again Grizzly. Have you heard any information about the status of Highway 20 on the Hill itself?

    One of my friends is stuck at Tweedsmuir Lodge... he's a visitor to the Valley and it sounds like it could be months before he'll be able to get his truck out of the Valley!

    This info you're posting is great - much more informative than what I can get off DriveBC. THANKS!

    Pelican Lady

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  2. Wishing you all the best down in the Bella Coola valley. We are usually buried in snow up here in Miocene in the winter so I can't imagine what you will be going through if all that water doesn't disappear for you soon.

    Heidi Redl

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