It comes as a surprise as officials focus on clogging the southern border, which has reached crisis point as thousands migrants seek entry from Mexico. 'Unpredictable storm fronts bring ice and significant snow accumulation throughout the extended winter season,' the Border Patrol warned. Customs and Border officials say some five million migrants have crossed over the U.S. southern border since January 2021 when the Biden administration took over. 'They're coming because they said that Biden told them to come, that we have an open border.' Huge container-sized gaps in the 30ft border wall allow migrants to walk right through, aided by a thinly-spread Border Patrol.