Pedzisa mutsara unotevera: Munenge muna 1200 UTC musi waNovember 7, Haiyan yakawana simba rayo guru nemhepo yakasimba yemaminitsi gumi uye barometric pressure ye895 mbar (hPa; ). Izvi zvakaita kuti ive dutu rechipiri rakasimba kwazvo muNorthwest Pacific Ocean rakanyorwa, zvichibva pakumhanya kwemhepo chete, pamwe chete naBess muna 1982 naMegi muna 2010, chete mushure me
Zano muna 1979. Maawa matanhatu gare gare, JTWC yakafungidzira kuti Haiyan yakanga yawana mhepo inopfuurira kweminiti imwe chete uye mhepo dzakasvika ku. Izvi zviri pamutemo zvinobatanidza Haiyan neTyphoon Meranti muna 2016 sedutu rechishanu rakasimba kwazvo rakanyorwa maererano nekumhanya kwemhepo, rakapfuurwa chete neTyphoon Ida (325 km / h) muna 1958, Typhoon Violet (335 km / h) muna 1961, Typhoon Nancy (345 km / h) muna 1961 uye Hurricane Patricia (345 km / h) muna 2015. Zvisinei, pamusana pokuti mhepo dzakanyorwa mumadutu dzaiva dzakakwirira zvisiri izvo muma1950 nema1960, zvinogona kutaurwa kuti Haiyan yakava dutu rechipiri rakasimba kupfuura mamwe ose akanyorwa, rechipiri chete kudutu rinonzi Hurricane Patricia muna 2015. (Zvakakosha kucherechedza, zvisinei, kuti mhepo dzaPatricia dzakayerwa zvakananga nendege dzevanovhima madutu, zviratidzo zvaive zvisina kuwanikwa zveHaiyan, saka chinyorwa hachina chokwadi uye kuenzanisa kusimba kwemadutu maviri kunonetsa.) Dutu racho rakaratidza zvimwe zvinhu zvedutu rinoputika rinoputika, kunyange zvazvo bhandi rakasimba rinoputika rakaramba riripo kurutivi rwokumadokero rwegadziriro yacho.