ARLINGTON, Va. (DC News Now) -- Ronald Reagan Washington National Airport (DCA) said it was closing all its runways Monday night in order to focus on snow removal at the airport. DCA posted about the closures on the X platform at 4:35 p.m. The post noted that crews would concentrate on snow removal as well as preventing refreezing on the airfield. Hundreds of flights at National Airport, Washington Dulles International Airport (IAD), and Baltimore/Washington International Thurgood Marshall Airport (BWI) were canceled or delayed throughout the day Monday due to the winter storm that made its way into and across the DMV and surrounding region. VIDEOS and PHOTOS: Winter storm leaves blankets of snow across DMV Dulles encouraged passengers Monday afternoon to check with their airlines directly about the status of flights, adding that airport staff members were monitoring runway conditions and clearing snow as needed. BWI shared a similar message for passengers on the X platform, noting that the storm brought "our biggest snowstorm in years."