FALLOUT PATTERN: There was a frontal system active in the New York City area on this date, developing winds from a WNW direction at 10–12 knots. As a consequence, little upwind fallout occurred in upper New York—Connecticut area; most downwind fallout was seaward, with considerable centralized fallout in Staten Island, Brooklyn, Queens, and western Long Island areas.
2. WASHINGTON, D.C. AREA
NATURE OF TARGET: Urban area.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 9–10 MT range.
NUMBER OF WARHEADS DELIVERED: Six warheads with possible unknown number of other nondetonating weapons.
BURST TYPE: Airburst and groundburst.
SPECIAL FEATURES: Same as 1 above.
FALLOUT PATTERN: Prevailing winds created a fallout pattern that was generally easterly with some deflection SSE. Because of Washington’s unique location, most fallout was into Maryland, and secondarily into Delaware and western New Jersey.
3. SAN ANTONIO, TEXAS AREA
NATURE OF TARGET: Urban area.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 9–10 MT range.
NUMBER OF WARHEADS DELIVERED: Three.
BURST TYPE: Airburst and groundburst.
SPECIAL FEATURES: Same as 1 above.
FALLOUT PATTERN: A frontal system was developing winds of 10–15 knots in a SE direction. Fallout was into South and East Texas, including the Houston area.
4. GREAT FALLS, MONTANA AREA
NATURE OF TARGET: U.S. Minuteman missile fields.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.
NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 25+.
BURST TYPE: Groundburst for maximum silo destruction. Some airburst detonations.
SPECIAL FEATURES: Intense surface radiation, with moderate to severe atmospheric fallout downwind.
FALLOUT PATTERN: Winds for late October were SE. Because of the attack nature, initial radioactivity was widespread over a large area. Radiation extended to Wyoming and South Dakota.
5. GRAND FORKS, NORTH DAKOTA AREA
NATURE OF TARGET: U.S. Minuteman missile fields.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.
NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 25+.
BURST TYPE: Groundburst for maximum silo destruction. Some airburst detonations.
SPECIAL FEATURES: Same as 4 above.
FALLOUT PATTERN: Winds were SE, hence fallout pattern developed over Minnesota, with some low-level fallout in Wisconsin.
6. MINOT, NORTH DAKOTA AREA
NATURE OF TARGET: U.S. Minuteman missile fields.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.
NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 45+.
BURST TYPE: Groundburst for maximum depth destruction. Some airburst detonations.
SPECIAL FEATURES: Same as 4 above.
FALLOUT PATTERN: Winds were SSE-S for attack date. Early fallout was concentrated in N. Dakota, with some fallout in S. Dakota and minor fallout in Iowa.
7. RAPID CITY, SOUTH DAKOTA AREA
NATURE OF TARGET: U.S. Minuteman missile fields.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.
NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 35+.
BURST TYPE: Groundburst for maximum depth destruction. Some airburst detonations.
SPECIAL FEATURES: Same as 4 above.
FALLOUT PATTERN: Winds were SSE. Fallout line was largely into S. Dakota and Nebraska, with development into Iowa and Missouri.
8. CHEYENNE, WYOMING AREA
NATURE OF TARGET: U.S. Minuteman and MX missile fields.
TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.
NUMBER OF WARHEADS DELIVERED: Unknown but estimated at 35+.
BURST TYPE: Groundburst for maximum depth destruction. Some airburst detonations.
SPECIAL FEATURES: Same as 4 above.
FALLOUT PATTERN: Winds were SSE. Primary fallout occurred in Wyoming, Kansas, Colorado, and Nebraska, with some development Into southeastern Missouri.
MONTANA
| Billings | 45D 48M North / 108D 32M West |
| Glasgow | 48D 13M North / 106D 37M West |
| Great Falls | 47D 29M North / 111D 22M West |
| Havre | 48D 33M North / 109D 46M West |
| Helena | 46D 36M North / 112D 00M West |
| Kalispell | 48D 18M North / 114S 16M West |
| Miles City | 46D 26M North / 105D 52M West |
| Missoula | 46D 55M North / 114D 05M West |
NEW YORK
| Central Park/Manhattan | 40D 47M North / 78D 58M West |
| Kennedy Airport | 40D 39M North / 73D 47M West |
| La Guardia Airport | 40D 46M North / 73D 54M West |
NORTH DAKOTA
| Bismarck | 46D 46M North / 100D 45M West |
| Fargo | 46D 54M North / 96D 46M West |
| Williston | 48D 11M North / 103D 38M West |
SOUTH DAKOTA
| Aberdeen | 45D 27M North / 98D 26M West |
| Huron | 44D 23M North / 98D 13M West |
| Rapid City | 44D 03M North / 104D 04M West |
| Sioux Falls | 43D 34M North / 96D 44M West |
TEXAS
| Austin | 30D 18M North / 97D 42M West |
| Corpus Christi | 27D 46M North / 97D 30M West |
| Houston | 29D 58M North / 95D 21M West |
| San Antonio | 29D 32M North / 98D 28M West |
WASHINGTON, D.C.
| Dulles Airport | 38D 57M North / 77D 27M West |
| National Airport | 38D 51M North / 77D 02M West |
WYOMING
| Casper | 42D 55M North / 106D 28M West |
| Cheyenne | 41D 09M North / 104D 49M West |
| Lander | 42D 49M North / 108D 44M West |
| Sheridan | 44D 46M North / 106D 58M West |
Radioactive fallout is created by thermonuclear weapons as a result of residual radiation, that is, radiation that occurs or is induced in particulate matter approximately one minute after detonation. In thermonuclear weapons especially, large numbers of high-energy neutrons are produced, which interact with elements in the air and on the ground; these elements then become radioactive and in turn emit beta and gamma radiation.