Pedzisa mutsara unotevera: Musi waSeptember 4, pashure pokuchinja kuva mamiriro ezvinhu akanaka zvikuru, Irma yakasimbiswa kuva dutu reChikamu 4. Sezvairamba ichiswedera pedyo neLeeward Islands, Irma yakawana nguva yechipiri uye yakasimba yekukurumidza kukurumidza, ichiva dutu reCategory 5 na12: 00 UTC pazuva rakatevera, nemhepo dze 175 mph (280 km / h). Dutu rine simba zvikuru rakaramba richipfuurira, nemhepo yakasimba inopfuurira kusvika 180 mph (285 km/h) pedyo na 18:00 UTC musi waSeptember 5. Irma yakawana mavara emhete panguva ino, nedutu rinoratidza hombe, symmetrical CDO uye inonakidza satellite chitarisiko. Irma yakaramba ichikura sezvaaiswedera pedyo neNorthern Leeward Islands. Anenge maawa masere gare gare, panenge pa05:45 UTC musi waGunyana 6, Irma yakasvika kumahombekombe ekuchamhembe kweBarbuda pakukwirira kwakanyanya, nekumanikidzwa kwakaderera kwedutu kwakadzika pa <unk> iyi yaive yakaderera muAtlantic kubvira
Dean muna 2007; dutu racho rakasvikawo kumhenderekedzo yegungwa nemhepo dzakasimba dzinosvika 180 mph (285 km / h). Irma akaramba achichengetedza simba rake kusvika na12:00 UTC musi wa6 Gunyana uye akaita mamwe mafambiro anotevedzana pazuva rimwe chetero, na11:15 UTC paSint Maarten, uye na16:30 UTC paVirgin Gorda, muBritish Virgin Islands, kunyangwe hazvo kumanikidzwa kwepakati kwedutu kwakanga kwasimuka zvishoma pamberi pekupinda kwayo kwechitatu.