High Winds... not to be underestimated

Two weeks ago was my first experience with the whites and infamous weather that it gets. The wind speeds were probably 40-60mph and I got knocked to my knees a few times as well as being forced to stagger about like I was drunk. One time even being forced to hang onto a rock on a cairn when the wind tried it's best to blow me off the mountain (Adams 4) . I knew the wind wasn't to be thought lightly of but a recent trip report on summitpost.org highlights the potential danger of high winds and why they shouldn't be toyed with. Enjoy the trip report.. after reading it I know I'll be more wary of high winds then I was before.

Even more fun is when you go up Washington on a calm morning and unexpectedly meet hurricane force winds on the way down - once it took me 3 hours to crawl from the base of the rockpile to LH with huge chunks of ice blowing above my head from out of the ravine. Fun times.

We had to turn around on our first attempt on Chimborazo when one of my rope team got lifted right off his feet by the wind - obviously an unsafe situation. Wind can also have some unexpected consequences. On the same climb, I took my goggles off momentarily and one of my contact lenses blew out of my eye and into the Amazon basin somewhere...

A while ago someone here posted great comments on the effects of wind -- what a hiker might experience at different wind speeds. Sort of a Beaufort Scale for hikers. It went something like, “at windspeed X you will not be able to stand upright . . .,” etc.

That would be interesting to see again, if anybody can provide it . . . or a link.

G.

A search showed that Waumbek posted a link to the Beaufort Scale:

From his post:
http://www.unc.edu/~rowlett/units/scales/beaufort.html

Jay

There was a recent injury in Huntington Ravine (12/3/05) when a very experienced ice climber was blown off his feet and slid ~400'. Especially when footing is tenuous, it doesn't take much wind to set you stumbling.

el-bagr said:

There was a recent injury in Huntington Ravine (12/3/05) when a very experienced ice climber was blown off his feet and slid ~400'. Especially when footing is tenuous, it doesn't take much wind to set you stumbling.

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very true - last year in south gully it was moderate winds (like 40 -50 mph) and there were time when i was clinging to my planted axe waiting for the gusts to pass to continue climbing - on steep ground like that it doesn't take much send you flying. quite nerve-racking really.

I have heard rumors thru second hand knowlege of tents being lifted and blown of the ridges in the pressies - don't know the truth to that tho.

highest I have been in is the low high 90's or 100's - once cresting to top of boot spur link and once the top of lions head - I mean you can't even walk and the noise is so loud!! didn't make it to far those days.


I can't imagine climbing on of those days where the winds are like 140 or 160mph = has to be impossible.

Wind (dynamic) pressure varies with the square of the wind speed. (It's also proportional to the barometric pressure.) A wind speed of 16mph has a dynamic pressure of about 1lb/sq-ft at sea level.

So, a wind of 64mph has a dynamic pressure of about 16lb/sq-ft and if we assume a standing human has an effective ("flat plate") area of about 5 sq-ft, the total force on the human would be about 80lb. Raise the wind to 128mph and the total force would be about 320lb. And of course, gusty winds will make these forces and their directions change rapidly.

I've read that humans tend to get picked up at wind speeds around 80mph.

Wind close to the ground (the boundary layer) is slower than the wind higher up. Justification for why it is easier to crawl than walk in high winds. (Works for the alpine plants, too.)

Happy hiking in the wind.

Doug