The effective step count in peak offshore cyclone wind gains showed no clear era change in two basins in 1982-2023

We measured how wind gain was spread across four six-hour steps in a 24-hour rapid-intensification window. We used fixed IBTrACS v04r01 records for the North Atlantic and eastern North Pacific in 1982-2023. We selected the strongest eligible window per storm. All five fixes had tropical storm or hurricane status and center distance to land of at least 200 km. Net wind gain was at least 30 kt. Effective step count was the square of total positive gain divided by the sum of squared positive gains. For NA, late minus early mean step count was -0.040, with a 97.5% year-bootstrap interval of -0.196 to 0.104. For EP, late minus early mean step count was 0.134, with a 97.5% year-bootstrap interval of -0.065 to 0.358. The eras were 1982-2002 and 2003-2023. These are conditional sample estimates. Wind rounding, changing observation methods, storm selection and the short record limit inference. The measure is not event duration and does not identify a physical cause. Code, fixed source rows, hashes, uncertainty draws and an independent audit are included.

tropical cyclone · rapid intensification · six-hour wind change · effective step count · IBTrACS · North Atlantic · eastern North Pacific · year bootstrap