Avoidable, stay on the ground or go land on the beach.....like others said.
But, had they been able to see the rotors, they might have been able to fly faster (depending on glider/hand/body position) through them and get to some better air (then slow down and land)....but can you see rotors?....that move??
You think you know where they are but the wind is shifting all over so it moves them around
....
When this happens the pilots on the ground should make sure there are lots of streamers all over the LZ.....so the pilots in the air can find a good spot to set her down......(or make sure there are lots in the LZ before you launch in this type of condition so you are ready for the nasty landing (there is your answer)).
Diev
Diev Hart
T2C 154, Sport 2-155, Falcon 3 195,
Super Sport 153, Super Lancer 200
FL, CL, FSL, AWCL, RLF, AT, TFL, TUR, XC, MNTR
http://www.dievhart.com/hangglide.html
http://tech.groups.yahoo.com/group/hgphotos/
http://www.hanggliding.org/viewtopic.php?t=25414 (HG.org Camera Mounts)
"The superior pilot uses his superior judgement to avoid having to use his superior skill"