Mezue nkebi ahịrịokwu na-esonụ: E jiriwo nwayọọ nwayọọ mee ka ụzọ ndị e si agaru nso dịkwuo mma, n'oge na-adịbeghịkwa anya, e wusawanyere ihe ndị e ji ekpuchi ala ahụ mgbe oké mmiri ozuzo na-ada n'akụkụ ebe ndịda. Ọdọ Mmiri Mont Blanc
ọdachi nke 1999 kpaliri nyocha dị ukwuu nke nchekwa ọwara okporo ụzọ n'ọtụtụ mba gụnyere Switzerland, a na-ezube kwalite nchebe dị ukwuu maka Grand St Bernard Tunnel. A machibidoro ịgba ọsọ 80 km/hour (50 mph) iwu n'ime ọwara ahụ.