Request for more data sets for Eric Knoff in the Gallatin NF Av Ctr

​From the other day -

PST (Propagation Saw Tests) tend to have a higher "false stable" ratio thanECTs(Extended Column Tests) but may be preferable when one has a deeper weakness of concern.

Eric Knoff(retired Snowbird) and current Gallatin NF Avalanche Center forecaster wrote a paper on horizontal pit-wall PSTs andpublished itat this fall's ISSW. Hisdata indicate that CPSTs share similar critical cut lengths as standard PSTs, with 75% of critical cut lengths falling within 10 cm of each other. Something to consider as they're much more efficient to conduct, especially in a standard ECT pit wall.

Eric was glad for the shout-out and sent on a request for more data - below is his email -

Drew,

Thanks for the CPST plug in your observation and Great Video! I highly appreciate it. I do think the PST and CPST work well with deep weak layers, as demonstrated with your vid. You definitely have to watch out for the falling column with CPST. There’s something with the way it propagates and releases that gives it a higher hazard rating than the standard PST and ECT. Even though the ECT is conducted in a similar style as the CPST, I rarely have ECT columns fall on me. Anyway – it’s something to think about when doing the CPST – mainly for personal safety.

I am still collecting data on the CPST and was wondering if you and the UAC crew could collect a data set or two for me?

A data set includes:

Test scores for

• Regular ECT
• Standard PST
• Cross Slope PST
• Weak Layer type and depth below surface
• Slope Angle
• Stability rating – Poor, Fair, Good, Very Good

A pit profile is helpful but not necessary

Any data is greatly appreciated.

I hope winter returns to your neighborhood and ours – it looks like we could all use it.

Give my best to the Wasatch.

Take er easy

Eric- [email protected]

SUBMIT DATA TO ERIC AT THE EMAIL ADDRESS ABOVE -

Quick video of ECT and CPST below -