Avoiding Being Blown Back
A while ago, I went through the BHPA incident reports for DSC sites. Being blown back over the Lord's \ Rushup ridge was one of the most common occurrences.
The rotor on the downwind side of the ridge can be severe - not a place you want to end up.
This article discusses strategies for avoiding this.
This was Ross's incident last year, kept pushing into wind and getting into increasingly strong compression rather than bearing off right which would have taken him away from hill and worst of compression. https://youtu.be/8u13VykYj1g
Again lots of good comments were made and lost on FB but Squirty Bob nailed it -
making friends with the wall and turned back to check he was on his feet and Ok. I didnt see your collapse as I was looking at Noe. The line you were flying is the "usual" line pilots fly to get the boost that takes you above ridge height and over the top of Lords. Because the wind was stronger than forecast You need to start thinking of changing your line so head into wind and away from the compression.When you first put your bar on you could have turned back towards Mam and pushed out as other people have said. be aware that the other wings infront of you were higher performance and further out into the valley. well done for posting vid and glad there were no injuries. as a general rule if things start to get dodgy go back to where they wernt.
Think of the hill as the top surface of a wing.
All the wind tries to get from A to B, but the stuff that finds the ridge in the way has to make a detour over the hill. To keep up with the rest it goes faster.
So 10 mph of wind.
45 degree slope.
Wind going up the slope has to go 14.142 mph to keep up.
At doesn't actually manage that so it carries on going faster for some distance after it reached the crest of the hill.
Now you can penetrate into 15mph, but you so have a sink rate of 2 mph.
So while you are in the lift the sink rate is adding to your speed into the angled wind. The horizontal wind is still 10mph.
Now you drop back over the summit and you have up to 14mph horizontal, and your sink rate does nothing to help. So you only have 1mph of penetration left, and it looks very iffy.
A little way up wind you are in the rising air, and your sink rate adds to your penetration.
Further up wind you are in the prevailing horizontal wind and can still penetrate the same.
Here is a link to the Facebook discussion of my incident: https://www.facebook.com/groups/238819502809825/permalink/2642496072442144
Agree with Squirty Bobs assessment of the technicalities of my incident. Gordon also posted a really nice description of how the wind would roll along the face as it was fairly far off:
What happened to the other guy behind the wall?You are close in, wind off to west, close to the highest point of the spine but still below it... Probably something spilled off the top and grabbed you. Rotor. As the wind gets more along the ridge it starts to roll along the face. I notice this when I start to get tipped into the ridge as well as tipped out by the lift... Happens at about 30 degrees wind. 60 degrees off...
I often see the "technicalities" of incidents discussed though and very rarely the human factors and often think the human factors have at least an equal part to play.
My mind was 90% consumed with my new bit of kit and not getting dragged because I couldn't grasp the risers as I wanted.