We thank Dr. Wilson for pointing out that the intense hurricane downward trend is better described as an active followed by a quiescent regime. The apparent sudden drop in hurricane frequency around the late 1960s also has been noted in Gray (1990) and Landsea (1993). Landsea et al. (1996) fitted a linear trend to the hurricane numbers to emphasize the overall long-term change that has taken place. In particular, we wished to emphasize that there has not been an upward trend in hurricane numbers, despite suggestions that such a trend might result from an enhanced greenhouse effect. We did not mean to imply that the decline in the numbers of hurricanes simply reflected a linear trend. We agree with Dr. Wilson, and with the analyses in Gray (1990) and Landsea (1993), that a more accurate description is that of an active regime during the 1940s through the 1960s, followed by a quiet period during the 1970s through the early 1990s, rather than a simple, linear downward trend in numbers.
Gray, W. M., Strong association between West African rainfall and US landfall of intense hurricanes. Science, 249, 1251-1256, 1990.
Landsea, C. W., A climatology of intense (or major) Atlantic hurricanes. Mon. Weath. Rev., 121, 1703-1713, 1993.
Landsea, C. W., N. Nicholls, W. M. Gray, and L. A. Avila, Downward trends in the frequency of intense Atlantic hurricanes during the past five decades. Geophys. Res. Lett., 23, 1697-1700, 1996.