From the NORAD/US Northcom twitter feed:
NORAD taking appropriate and prudent steps to ensure adequate posture to respond quickly to any incidents involving aviation in Canada.
For MilcomMP readers here are the current NORAD UHF freqs.
228.900 234.600 235.900 238.400 252.000 254.200 260.900 265.400 270.200 271.000 274.000 277.600 278.000 281.600 282.600 288.400 293.600 316.300 320.600 324.000 327.900 328.000 355.200 364.200 (AICC Nationwide) 386.000 MHz