The 1991 Atlantic hurricane season was the first season in over 24 years in which no hurricanes developed from tropical waves, which are the source for most North Atlantic tropical cyclones. The hurricane season officially began on June 1, and ended on November 30. It was the least active in four years due to higher than usual wind shear across the Atlantic Ocean. The first storm, Ana, developed on July 2 off the southeast United States and dissipated without causing significant effects. Two other tropical storms in the season – Danny and Erika – did not significantly affect land. Danny dissipated east of the Lesser Antilles, and Erika passed through the Azores before becoming extratropical. In addition, there were four non-developing tropical depressions. The second depression of the season struck Mexico with significant accompanying rains.