▁( 5 0   m ph ), ▁and ▁on ▁the ▁same ▁day ▁the ▁storm ▁began ▁interact ing ▁with ▁developing ▁Trop ical ▁Storm ▁Christ elle ▁to ▁the ▁west . ▁On ▁January   5 , ▁increased ▁she ar ▁weak ened ▁Bent ha , ▁and ▁by ▁the ▁following ▁day ▁the ▁storm ▁d eter ior ated ▁into ▁a ▁tropical ▁de pression . ▁The ▁system ▁passed ▁about ▁ 2 5 0   km ▁( 1 5 5   mi ) ▁north ▁of ▁Ré union ▁on ▁January   6 , ▁diss ip ating ▁shortly ▁there after ▁near ▁T rom elin ▁Island ▁while ▁being ▁absor bed ▁into ▁Christ elle . ▁ ▁Both ▁Bent ha ▁and ▁Christ elle ▁brought ▁g ust y ▁wind s ▁and ▁ra inf all ▁to ▁Maur it ius , ▁and ▁caused ▁Ré union ▁to ▁be ▁under ▁a ▁cy clone ▁watch ▁for ▁five ▁days . ▁ ▁In ten se ▁Trop ical ▁Cy clone ▁Dor ina ▁ ▁The ▁I TC Z ▁spawn ed ▁an ▁area ▁of ▁con ve ction ▁and ▁a ▁vor tex ▁in ▁the ▁n ort he astern ▁portion ▁of ▁the ▁bas in ▁on ▁January   1 8 , ▁which ▁organized ▁into ▁a ▁tropical ▁disturb ance ▁that ▁day . ▁It ▁initially ▁moved ▁sout heast ward ▁under ▁the ▁influence ▁of ▁the ▁mon so on , ▁although ▁it ▁gradually ▁rec ur ved ▁back ▁to ▁the ▁south west . ▁On ▁January   1 9 , ▁the ▁system ▁intens ified ▁into ▁Trop ical ▁Storm ▁Dor ina , ▁and ▁on ▁the ▁next ▁day ▁the ▁J TW C ▁initi ated ▁advis ories ▁on ▁it