The phrase "increased storminess" means that there is more frequent or intense occurrence of storms.
Sentences with «increased storminess»
These experiments also show a decline in storminess and wind intensity eastwards into the Mediterranean (Busuioc, 2001; Tomozeiu et al., 2007), but with localised increased storminess in parts of the Adriatic, Aegean and Black Seas (Guedes Soares et al., 2002). (ipcc.ch)
However, there is no evidence of increased storminess over the last 30 years. (junksciencearchive.com)
This includes evidence for increased storminess at the end of the Little Ice Age. (junksciencearchive.com)