 Nyorai kupfuurira kweiyi ndima - Chikamu chikuru cheSR 504 chakaparadzwa muna May 18, 1980, kuputikaweGomo reSt. Helens uye lahar yaro yakatevera paNorth Fork Toutle River. Hurumende yenyika yakavakazve mugwagwa mukuru kubva muna 1988 kusvika muna 1997, ichiuendesa kuchamhembe uye ichibatanidza kunzvimbo itsva dzinotsanangura paColdwater Ridge naJohnston Ridge. Chikamu chenzira yekare pedyo neTutle River Sediment Dam chakasainwa senzira yechimbichimbi. Kuenderera mberi kwekuputika kwemakomo paGomo reSt. Helens, kunyanya pakati pemakore ekuma2000, kwakaguma nekuvharwa nekubviswa munzira huru panguva dzakasiyana siyana. 