Nearly 100 million Americans under wind chill warnings or advisories. GOP candidates make final push ahead of Iowa caucuses. No end in sight as Israel-Hamas war hits100-day mark. U.S. officials press Israel to change tactics. How the Iowa caucuses work. Ukraine struggles to defend against Russian invasion as aid dries up. Iowa high school principal who shielded students during shooting dies. Iceland volcano erupts.

Tracking another cross country storm. Trump back in court following Iowa victory. Republican debate canceled ahead of New Hampshire primary. Frigid temps and travelchaos felt across U.S. Audio obtained from Defense Secretary Lloyd Austin's 911 call. Gilgo Beach suspect charged with fourth murder. U.S. continues strikes againstHouthis in Yemen. Brothers elected mayors of neighboring New Jersey towns.