THE EXPERIENCED COMMERCIAL PILOT WAS ATTEMPTING TO TAKE OFF FROM A MOUNTAIN LAKE WITH TWO HUNTERS ABOARD. WIND CONDITIONS AT THE TIME WERE ESTIMATED AS GUSTING TO 45 KNOTS. SHORTLY AFTER LIFT OFF THE PILOT STATED THAT HE ENCOUNTERED A STRONG DOWNDRAFT. HE SAID THAT HE WAS UNABLE TO MAINTAIN DIRECTIONAL CONTROL OR ALTITUDE, AND SUBSEQUENTLY CRASHED ABOUT 200' FROM THE SHORELINE. THE PILOT SAID THAT HE COULD HAVE PREVENTED THE ACCIDENT HAD HE ELECTED TO STAY ON THE LAKE UNTIL THE WIND HAD SUBSIDED.