To me, if whatever is shown and you're cutting it close, you're screwed.
Period.

Start finding better air, be looking for landing spots on a long final glide. Better to land in a controlled environment than waiting for a last minute, "hope my great piloting precludes a broken sailplane"!

This from someone that has a lot of off airport landings, one was in a spot (in a borrowed 1-26) that even local hang glider pilots said was impossible.

Just my thoughts.......