This analysis counts hurricanes with rapid intensification defined by an increase of >= 30 knots in 24 hours. It also counts more extreme categories which are inclusive (storms with >= 40 knots are also >= 30 knots) Then divides the number of RI hurricanes in each category by the total number of hurricanes for the year.

In general >=30 knot RI is common, the majority of hurricanes have at least one 24 hour period of RI. Variations in more extreme RI appear to come in recent multi-year clusters, e.g. 2005-2010 and again 2015-17. The more common >= 30 knots, is probably not very meaningful anymore.

Another plot below includes all tropical storms in the denominator and tropical storms with RI in the numerator. The drop in the lowest category RI is almost undoubtedly due to more TS being detected and named. I think the reason for the downward trend in RI versus TS is the detection of large numbers of weak storms using the scatterometer. Those are marginal to begin with and have a lower chance of RI.

Another plot below shows the trend of rapid weakening of storms that are not over land. That's obviously a crucial distinction since storms always weaken over land, often rapidly. Storms with the highest rates of weakening are included in the rapid intensification table. Some storms rapidly weakened in high latitudes which is expected and should show no trend. However, others like Beulah (1967) "unexpectedly collapse" in low latitudes, or are weakened rapidly by a dry air mass like Allen (1980) or proximity to land like Mitch (1998). It's possible that the slowing of hurricanes leads to more weakening. It's also possible that due to the increase in the strongest storms there are more opportunities for rapid weakening.

The final plot below shows RI for the period 1982 to 2009. According to an article in the Washington Post, A 2019 study in the journal Nature ( https://www.nature.com/articles/s41467-019-08471-z) documented a trend toward more rapidly intensifying hurricanes in the Atlantic Ocean between 1982 and 2009, and used a model that determined it would have been unlikely without human-caused climate change. There is a slight increase in RI in that interval due to the start and end points. However the paper uses an RI ratio which is the number of RI periods (24 hours) divided by the total number of 24h periods.

The problem with the ratio seems to be that the numerator is often zero (shown in their fig 3b to the left) due to too few hurricanes in that year. The zeroes makes the trend sensitive to the start and end points, unlike the blue points in the charts below. The red and black points are sensitive to starting and ending points. The upward trends since 1950 may be the most valid. Put another way, it appears that storms with 70 knot RI have become much less rare as shown in the table below. Also the RI ratio (calculated similarly to the nature paper) has more data to work with, and a slope of 3.9e-04 versus 2.4e-03 in the 1982-2009 interval. Note: to match the nature plots (more or less) I had to use > 30 knots instead of >= 30 knots for the a 24 hour RI threshold. The caption for fig 3b indicates that they using "above 30 knots" i.e. >= 35 knots.


We can cut the slope to 3.7e-04 by going back to 1920, although with the caveat that the pre-satellite data has a considerable number of missing observations and completely missed storms which may increase the weight of RI storms.


Here's a list of RI storms since 1950. Some of the more recent storm numbers have been validated from other sources. Peak wind column is from the list of strongest Atlantic storms https://en.wikipedia.org/wiki/List_of_Atlantic_hurricane_records#Strongest_by_1-minute_sustained_wind_speed. Preceding the table below are Labor Day (1932) and Cuba (1935) hurricanes. Undoubtedly there are other strong storms in pre-satellite, pre-hurricane hunter eras that would have be included if their peak winds happened to be measured.

(Note: all numbers are in knots)
YearName24h
inc
36h
inc
6h
inc
peak
wind
24h
decr
1950BAKER303510
DOG353510-35
ITEM304010
KING505020
1951ABLE354010
CHARLIE354515
EASY304010-30
HOW304010
1952CHARLIE355510
EASY405010
FOX556020
1953CAROL406010
EDNA303510
FLORENCE455015
HAZEL304010
1954ALICE454515
CAROL354010
DOLLY353510
HAZEL303010
ALICE303510
1955CONNIE354010
DIANE303010
FLORA303010
GLADYS354015
IONE404515
HILDA505515
JANET406010150
KATIE405010
1956ANNA454515
BETSY304010-30
FLOSSY304010
1957AUDREY354510
FRIEDA303010
1958CLEO455515
DAISY305015
ELLA355515
FIFI354510
HELENE455515
ILSA304010-30
19591959169N26274354010
DEBRA354515
GRACIE354515
HANNAH304015
JUDITH303010
1960CLEO40505
DONNA304510
ETHEL607020-30
1961BETSY354010
CARLA303510
DEBBIE354015
ESTHER404515-30
FRANCES404515-35
HATTIE456515
1962ALMA304010
1963ARLENE404510-35
BEULAH304510-30
1963253N2629330355
EDITH506020
FLORA456020
19641964210N19314304010
CLEO456515
GLADYS405020
HILDA456020
ISBELL405515
1965ANNA405510
BETSY505520
CAROL304010
ELENA304010
1966ALMA505530-30
BECKY404030
CELIA404510
FAITH354520
INEZ355015-50
1967CHLOE354510
BEULAH456015-55
DORIA304025
FERN454515
1968ABBY35355
DOLLY353515
1969BLANCHE454540
CAMILLE608525150
DEBBIE354520
FRANCELIA354515
GERDA658025
HOLLY454515
INGA304010
MARTHA353510
1970ALMA454530
CELIA707540
ELLA455520
19711971216N31297455515
BETH404515
FERN355015
EDITH657520
1972BETTY303520
1973ALICE354010
BRENDA353520
FRAN353510
1974BECKY455515
CARMEN456520
FIFI:ORLENE405515
GERTRUDE353520
1975BLANCHE35405
CAROLINE356030
ELOISE405010
FAYE355010
GLADYS404010-35
1976BELLE456015
CANDICE303025
FRANCES353515-30
HOLLY404020
1977ANITA657030150
CLARA353520
EVELYN354015
1978CORA555515
ELLA506020-55
GRETA304015
KENDRA353510
1979BOB354510
DAVID608020150
FREDERIC304010
GLORIA354010
HENRI404510
1980ALLEN456015165-55
BONNIE404020
GEORGES304015
FRANCES354510
IVAN303510
JEANNE303510
1981FLOYD355010
GERT405010
HARVEY455530-35
IRENE304010
KATRINA354510
1982ALBERTO505025
DEBBY406015-40
1983ALICIA304015
BARRY30405
CHANTAL354010
1984DIANA405015-30
1985DANNY354510
ELENA354510
GLORIA355520-45
KATE354015
1986EARL405015
FRANCES354510
1987EMILY607025
1988DEBBY354015
GILBERT505520160
HELENE304510
JOAN:MIRIAM455515-40
1989CHANTAL354510
FELIX303510
GABRIELLE304010
HUGO506015
1990BERTHA303510
DIANA354010
ISIDORE304010
NANA304010
1991BOB304010
CLAUDETTE557020-30
1992ANDREW659020150
BONNIE455520
CHARLEY305010
1993GERT405015
HARVEY353515
1994FLORENCE353515
1995ALLISON30355
ERIN303010
FELIX405010
HUMBERTO30405
IRIS404020
LUIS456520
MARILYN30405
OPAL506020
ROXANNE455515
1996BERTHA303520
EDOUARD506020-30
HORTENSE304515-30
ISIDORE354010
MARCO30355
1997DANNY354010
ERIKA303515
1998BONNIE304010
DANIELLE405515
EARL354520
GEORGES404515-35
JEANNE304010
MITCH456015155-55
1999CINDY354515-30
BRET557030
FLOYD405015-30
GERT304010
IRENE303015
LENNY506020-50
2000ALBERTO304010-40
DEBBY354510
FLORENCE353520
ISAAC556020-30
JOYCE304010
KEITH658025-45
MICHAEL303010
2001ERIN506515
FELIX355010
HUMBERTO305015
IRIS455030
MICHELLE456015
2002GUSTAV303515
ISIDORE404515
LILI354515-30
2003FABIAN456015
ISABEL455515
2004ALEX355015-40
CHARLEY355030
DANIELLE354510
FRANCES355515
IVAN556525
JEANNE303515
KARL405015-35
2005CINDY35405
DENNIS506520
EMILY456025
KATRINA505525150-35
RITA608525155-40
STAN304010
WILMA9510555160-30
BETA305015
2006FLORENCE303010
GORDON405515
HELENE304010
2007DEAN656520150
FELIX8510035150-35
HUMBERTO555525
KAREN303515
LORENZO404010
2008BERTHA556020-40
DOLLY304015
GUSTAV607025
HANNA303510
IKE707030
OMAR455520-45
PALOMA506020
2009FRED507020
IDA455510
2010DANIELLE304515
EARL406010-40
IGOR657025
JULIA507520-35
KARL557015
LISA404015
PAULA355515
TOMAS355015
SHARY303510
2011KATIA303510-35
OPHELIA405015-50
RINA506015-35
2012CHRIS303510
GORDON354015
KIRK354510
MICHAEL505515
SANDY405515-30
2013BARBARA303010
2014BERTHA303010
GONZALO355015
2015DANNY455515-40
FRED354510
JOAQUIN455520-45
2016ALEX303010
GASTON354510
MATTHEW758525-30
NICOLE405515-45
OTTO404015
2017FRANKLIN353510
HARVEY405510
IRMA456015155
JOSE406015-30
KATIA404520
LEE354515
MARIA708535150
NATE404515
2018BERYL354015
CHRIS304015
FLORENCE506015-40
MICHAEL355010
OSCAR303510
2019DORIAN354515160-40
JERRY354510
LORENZO405015-40
2020HANNA304010
GENEVIEVE507025-35
LAURA556520
TEDDY354020
SALLY303520
DELTA659020
EPSILON455515
ZETA354015
ETA709025
* 2020 data from IBTRACS is provisional, containing a Pacific storm and missing some Atlantic storms

Code: hurricanes.py | elevations.py | Data: hurdat.csv | Instructions: README
Trends in rapid intensification of hurricanes (percent of all hurricanes):


If all tropical storms are included the percentage drops as more TS are detected:

Maximum decrease in winds in 24 hours (not over land):

Interval matching Nature paper: