Tropical Storm Olaf (1997)

Tropical Storm Olaf

Tropical storm (SSHWS/NWS)
Satellite image of the storm near its first Mexican landfall
Formed	September 26, 1997
Dissipated	October 12, 1997
Highest winds	1-minute sustained: 70 mph (110 km/h)
Lowest pressure	989 mbar (hPa); 29.21 inHg
Fatalities	18 total
Areas affected	Mexico, El Salvador, Guatemala
Part of the 1997 Pacific hurricane season

Tropical Storm Olaf was an erratic and long-lived tropical cyclone that brought heavy rainfall to regions of Mexico, which would be devastated by Hurricane Pauline a week later. The sixteenth named storm of the 1997 season, Olaf formed on September 26 off the southern coast of Mexico. It moved northward and quickly intensified, reaching peak winds of 70 mph (120 km/h) before weakening and hitting Oaxaca as a tropical depression. In Mexico, El Salvador, and Guatemala, the system brought heavy rainfall, which killed 18 people and caused flooding and damage. It was originally thought that Olaf dissipated over Mexico, although its remnants continued westward for a week. It interacted with Hurricane Pauline, which caused Olaf to turn to the southeast and later to the north to strike Mexico again, finally dissipating on October 12.

The origins of Olaf were from a tropical wave first noted over Central America on September 22. It moved slowly through the eastern Pacific Ocean, and gradually developed an area of convection. Concurrently, an upper-level low-pressure area moved from the Gulf of Mexico across Mexico into the Pacific, which produced wind shear across the region; wind shear is the difference in wind speed and direction in the atmosphere, and is usually harmful to tropical cyclogenesis. The disturbance associated with the tropical wave persisted and developed outflow. This caused the upper-level low to move away from the system. On September 26, it was sufficiently organized to be classified Tropical Depression Seventeen-E, while located about 345 miles (560 km) south of the Gulf of Tehuantepec.