Recurrence intervals of hurricanes like other natural disasters, hurricanes occur periodically. for example, let's say a particular stretch of coast has been hit by 15 hurricanes over the last 120 years; therefore, the average recurrence interval of hurricane in this region is, therefore, 120/15 = 8 years [ie., number of years of observations divided by number of events, the probability (expressed in %) of any future occurrence of a hurricane for this stretch of coast in any given year is therefore, simply the inverse of the recurrence interval. if recurrence interval is 8 years, the probability is (1/8)* 100- 12.5% [note, we multiply by 10 to get 96). 80 w 40 n 30 n 30°n return period (years) major hurricane (-96kt) the map on right shows coastlines in eastern springboard of united states, considered at risk from hurricane strikes. numbers within the colored circles represent recurrence intervals of 100w hurricanes that were category 3 or higher that passed within 65 miles of that location. [this map was produced from historical weather data collected] 14-22 23-32 33-52 ● 53-120 121-290o coastal county 80-w 60 w