The timing of the first snowfall can significantly impact travel and safety. Early snow in September and October may affect mountain passes like I-90 over Lookout Pass and US 12 over Lolo Pass. By November, major interstates such as I-80 in Pennsylvania and I-70 in Colorado could see hazardous conditions. Snow-related crashes account for 24% of weather-related accidents annually, with over 1,300 fatalities and 116,800 injuries. El Niño's influence may delay snow in northern regions, potentially altering typical preparation timelines. Drivers should remain vigilant, especially on bridges and overpasses, which can become slick with minimal snowfall.