Impacts on the Moon can be observed as flashes of light with a typical duration of a fraction of a second. The first lunar impacts were recorded during the 1999 Leonid storm. Subsequently, several continuous monitoring programs were launched. , the largest observed lunar impact occurred on September 11, 2013, lasted 8 seconds, and was likely caused by an object in diameter. Each year, several mostly small NEOs pass Earth closer than the distance of the Moon. On August 10, 1972, a meteor that became known as the 1972 Great Daylight Fireball was witnessed by many people; it moved north over the Rocky Mountains from the U.S. Southwest to Canada. It was an Earth-grazing meteoroid that passed within of the Earth's surface, and was filmed by a tourist at the Grand Teton National Park in Wyoming with an 8-millimeter color movie camera. On October 13, 1990, Earth-grazing meteoroid EN131090 was observed above Czechoslovakia and Poland, moving at along a trajectory from south to north. The closest approach to the Earth was above the surface. It was captured by two all-sky cameras of the European Fireball Network, which for the first time enabled geometric calculations of the orbit of such a body. On March 18, 2004, LINEAR announced that a asteroid, 2004 FH, would pass the Earth that day at only , about one-tenth the distance to the Moon, and the closest miss ever noticed until then. They estimated that similar-sized asteroids come as close about every two years. On March 31, 2004, two weeks after 2004 FH, set a new record for closest recorded approach above the atmosphere, passing Earth's surface only away (about one Earth radius or one-sixtieth of the distance to the Moon). Because it was very small (6 meters/20 feet), FU162 was detected only hours before its closest approach. If it had collided with Earth, it probably would have disintegrated harmlessly in the atmosphere. On February 4, 2011, an asteroid designated , estimated at in diameter, passed within of the Earth, setting a new record for closest approach without impact, which still stands . On November 8, 2011, asteroid , relatively large at about in diameter, passed within (0.85 lunar distances) of Earth. On February 15, 2013, the asteroid 367943 Duende () passed approximately above the surface of Earth, closer than satellites in geosynchronous orbit. The asteroid was not visible to the unaided eye.