Old Faithful, on time, August 18, 2:42 PM. Neither the biggest nor the best, but certainly the most reliable and famous of Yellowstone’s geysers.
I’ve watched Old Faithful several times, including twice in August. This eruption seemed larger than most; the height can vary from 106 to 185 feet (32 to 56 meters) and volume from 3,700 to 8,400 U.S. gallons (14 to 32 kL). On Thursday morning at 9:15 there were maybe 300-350 watching; on Saturday afternoon when this photo was taken, more than 1,000.