An arctic blast is sweeping across the country with millions under wind chill alerts where temperatures could dip 20 to 45 degrees below average. Meanwhile, winter storms have grounded flights and icy roads are causing dangerous driving conditions. NBC's Jesse Kirsch reports and TODAY's Dylan Dreyer tracks the latest forecast. With former President Donald Trump holding a commanding lead in the latest poll before Monday's GOP caucus, Nikki Haley and Ron DeSantis are battling it out for second place. NBC's Kristen Welker weighs in and Steve Kornacki breaks down the numbers on TODAY. As the Israel-Hamas war reaches 100 days, Israel's Netanyahu is vowing to increase its military pressure and keep fighting. Meanwhile, Hamas is marking the grim milestone by releasing a disturbing new video showing three of the hostages who are still held in Gaza. NBC's Richard Engel reports for TODAY. The search continues for two U.S. Navy SEALs who went missing off the coast of Somalia during a nighttime mission. The SEALs fell into the water while attempting to board a boat in the Gulf of Aden. NBC's Molly Hunter reports for TODAY.