dan fredinburg was one of four americans killed when a massive earthquake struck nepal on saturday , causing a wall of ice and rock to engulf the base camp .
the 33-year-old , who was with three colleagues and had been navigating the area for google maps , was given the messages by his girlfriend ashley arenson just before he set off on the expedition .
dan fredinburg was one of three americans killed when the massive earthquake struck nepal on saturday , killing more than 3,700 people .
he was given letters by friends and family when he reached the summit .