Help interpreting CAIC info

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colospgs
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Help interpreting CAIC info

Post by colospgs » Fri Feb 05, 2021 11:46 am

Hi all,

As someone who has only taken a basic avalanche safety course, I have a question for those of you with more education than that. On the CAIC website, after choosing a region, I see under each avalanche problem a graphic showing aspect and elevation. As I check this site often as the season moves on, I noticed that in the regions I check, the aspects usually shaded in as problem areas are N, NE, E, SE. This season I have never seen W or SW shaded in in the regions I check.

So my question is: How am I to interpret the danger on those aspects that are not shaded in? No danger? (That doesn't seem right) So little danger that it's not worth mentioning? (Hmm, doesn't seem right either)

As a for instance, look at the SW route on Yale, or the NW slopes on Pikes when those aspects are not shaded in on CAIC. Let's assume the danger color code is yellow or orange for the region.
Last edited by colospgs on Fri Feb 05, 2021 11:59 am, edited 1 time in total.
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Tornadoman
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Re: Help interpreting CAIC info

Post by Tornadoman » Fri Feb 05, 2021 11:54 am

https://avalanche.state.co.us/forecasts ... it-county/

Today's avalanche forecast for Summit/Vail shows the danger at all elevations and aspects (including West, etc). Those aspects are certainly not highlighted as often, but I have seen them outlooked several times this year.

As for interpretation, I would take it as 'less danger' not 'no danger' if an area isn't highlighted on the avalanche rose.
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Re: Help interpreting CAIC info

Post by spoony » Fri Feb 05, 2021 12:01 pm

colospgs wrote:
Fri Feb 05, 2021 11:46 am
Hi all,

As someone who has only taken a basic avalanche safety course, I have a question for those of you with more education than that. On the CAIC website, after choosing a region, I see under each avalanche problem a graphic showing aspect and elevation. As I check this site often as the season moves on, I noticed that in the regions I check, the aspects usually shaded in as problem areas are N, NE, E, SE. This season I have never seen W or SW shaded in in the regions I check.

So my question is: How am I to interpret the danger on those aspects that are not shaded in? No danger? (That doesn't seem right) So little danger that it's not worth mentioning? (Hmm, doesn't seem right either)

As a for instance, how would you interpret the danger on the SW route on Yale, or the NW slopes on Pikes when those aspects are not shaded in on CAIC? Let's assume the danger color code is yellow or orange for the region.
Those dials are intended to highlight where problems are more likely to arise, but I would not interpret them as meaning that a western aspect is danger free if the dial is not shaded...it is just that the problems are less likely to occur on those aspects. I also would not interpret a lack of shading to mean that a route that predominantly travels on a western slope, like Yale's SW slopes is free from danger. For example, on Yale's SW route, you may pass below eastern slopes that are more likely to slide even if you are not specifically traveling directly on top of a slide prone slope.

Also, the reason you are less likely to see W or SW shaded is because the wind in Colorado loads up snow on eastern aspects more readily (and northern aspects hold more snow because of the lack of sun).

As with all things avalanche, the recommendations and ratings by CAIC should merely serve as a general guide and you should pay specific attention to the area where you might be traveling to be safe.
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Re: Help interpreting CAIC info

Post by Chicago Transplant » Fri Feb 05, 2021 12:03 pm

The rose is typically highlighting specific areas of concern.

So for wind loading in the Sawatch Zone (Yale), the NE, E and SE above treeline aspects are currently the biggest likelihood of risk for wind slab due to the direction of wind loading favoring those aspects. It does not mean the SW facing slope has no danger, but that an abundance of caution should be used on wind loaded slopes, which are most likely to be NE-E-SE facing.

As you can see in the Vail/Summit Zone, storm slab is a concern everywhere as is persistent slab. That is because we have had over a foot in the last couple of days and over 2 feet in the last week with more falling out my window as I type this.
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Re: Help interpreting CAIC info

Post by RobLowe » Fri Feb 05, 2021 12:05 pm

I second Tornadoman. Unshaded areas do not mean no danger; that’s a crazy interpretation. I think of unshaded as less likely, but that less likely is still subject to change based on the conditions that I see once I’m out there. Forecast is a good starting point and something to screenshot and keep in mind before you get out there, but it’s not infallible.

For example, I was in the Sangres last weekend. Only North to SE above tree line were shaded. I had significant whoomphing, cracking, and snow movement at tree line (unshaded) and on unshaded slopes (W to S). For me, the risk exceeded my tolerance level and my day was done. It was the worst snow day I had seen in 15 days out this winter at or above tree line.
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Re: Help interpreting CAIC info

Post by curt86iroc » Fri Feb 05, 2021 12:12 pm

Agstrohmeier
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Re: Help interpreting CAIC info

Post by Agstrohmeier » Fri Feb 05, 2021 2:28 pm

curt86iroc wrote:
Fri Feb 05, 2021 12:12 pm
this may help a little also...

https://utahavalanchecenter.org/avalanche-danger-scale
That's some good info.

An avalanche instructor recently told me she looks at "unshaded" areas as one level less than the shaded areas. So if it is conaiderable, with persistent slab on N-E-SE, she would look at the persistent slab risk on NW-W-S as moderate. I haven't found anything that states this formally, but my main takeaway was it is often still present, even if not shaded.
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Re: Help interpreting CAIC info

Post by Bean » Fri Feb 05, 2021 2:39 pm

For what it's worth, the one time I went for a ride it was on a westerly aspect with no mentioned avalanche problems and the slope was only about 31 degrees. Fortunately it was very small, though had it carried me over some cliffs that would've made for a very bad day.

The closest I ever came to being in a large avalanche, my party remotely triggered a slab avalanche on a south aspect, and the bulletin mentioned nothing relating to what we encountered.

I'm at the point in my life where the avalanche forecast is interesting to read, but between having a family to come home to and my past experiences, I manage my risk completely through terrain with little consideration for if a specific slope "should" be safe until I have absolute confidence in the snowpack (e.g. fully-consolidated spring snowpack).
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Re: Help interpreting CAIC info

Post by TomPierce » Fri Feb 05, 2021 3:27 pm

Bean wrote:
Fri Feb 05, 2021 2:39 pm
For what it's worth, the one time I went for a ride it was on a westerly aspect with no mentioned avalanche problems and the slope was only about 31 degrees. Fortunately it was very small, though had it carried me over some cliffs that would've made for a very bad day.

The closest I ever came to being in a large avalanche, my party remotely triggered a slab avalanche on a south aspect, and the bulletin mentioned nothing relating to what we encountered.

I'm at the point in my life where the avalanche forecast is interesting to read, but between having a family to come home to and my past experiences, I manage my risk completely through terrain with little consideration for if a specific slope "should" be safe until I have absolute confidence in the snowpack (e.g. fully-consolidated spring snowpack).
Yep, +1K

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