USPS workers in bad weather

What do usps/other postal workers do about weather conditions? Like when ice is very bad etc? I’m so worried about my fiancé starting his new job and in the description “work in all weather conditions” makes me so uncomfortable. Just today the roads are so bad and our mail was still delivered and I’ve read so many wrecks today in my town. I’m going to be a worried nut case everyday he works and has to drive or walk in weather like this. ☹️