Gusts of wind up to 50 miles per hour. Torrents of rain from a pounding nor'easter. Temperatures in the mid-thirties. Two inches of standing water at the staging area. Flooding streams. Extreme risk of hypothermia for 26.2 miles. And twenty thousand other runners who have been looking forward to this moment for at least a year--some, for many years--and not a one willing to quit now. It is the 111th running of the Boston Marathon.