TONIGHT. TERRY, THANK YOU. >>> WE'RE GOING TO TURN NEXT MEANWHILE TONIGHT TO THE DANGEROUS COLD MOVING IN, WIND CHILLS IN THE NORTHEAST REACHING 50 BELOW ZERO IN THE COMING DAYS. 58 MILLION AMERICANS IN THE PATH OF THIS BRUTAL AND LIFE-THREATENING COLD, THEY'RE SAYING, FROM MONTANA TO MAINE. ALREADY HITTING THE MIDWEST TONIGHT, MOVING EAST, WHILE IN THE SOUTH, LOOK AT THIS. NEARLY HALF A MILLION HOMES AND BUSINESSES STILL WITHOUT POWER AFTER TREES AND POWER LINES CAME DOWN. AND THIS ICE STORM LASTING FOR DAYS NOW. SNOW MOVING NORTH TODAY IN WISE, VIRGINIA. TONIGHT, BOSTON ALREADY DECLARING AN EMERGENCY AND OPENING WARMING CENTERS. SENIOR METEOROLOGIST ROB MARCIANO ON THE ICE TONIGHT AND THE COLD MOVING IN. >> Reporter: TONIGHT, THE SOUND OF HEAVY EQUIPMENT AND CHAINSAWS PIERCING THE AIR NORTH OF AUSTIN. A RACE TO CLEAN UP A TANGLED MESS OF ICE-COVERED TREES AND POWER LINES. LIMBS SNAPPING AFTER DAYS OF ICE AND SLEET. >> WE ARE EXPERIENCING ONE OF THE MOST WIDESPREAD ICE STORMS TO HIT AUSTIN AND CERTAINLY ONE OF THE WORST. >> Reporter: HUNDREDS OF THOUSANDS IN THE DARK ACROSS THE STORM ZONE. OUR ALEX PRESHA SOUTH OF LITTLE ROCK, ARKANSAS, WITH CREWS RESTORING POWER AND FACING MULTIPLE CHALLENGES. >> SLICK ROADS AND THE TERRAIN AND ICE, YOU KNOW, TREE LIMBS FALLING OUT OF TREES. >> Reporter: AS THE SYSTEM PUSHES EAST, IT'S PULLING DOWN THE COLDEST AIR OF THE SEASON SO FAR. BOSTON DECLARING A COLD EMERGENCY, CLOSING SCHOOLS, AND OPENING WARMING CENTERS. >> BY SUNSET TOMORROW, IT IS DOWN INTO THE SINGLE DIGITS, AND THE WIND IS GOING TO BE HOWLING. >> Reporter: THAT WIND WILL MAKE IT FEEL LIKE MORE THAN 50 BELOW IN SPOTS. NEW HAMPSHIRE'S GOVERNOR WARNING FAMILIES NEED TO TAKE THIS SERIOUSLY. >> AT NEGATIVE 30 DEGREES, HYPOTHERMIA CAN SET IN IN JUST TEN MINUTES. AND WE KNOW IT'S GOING TO BE EVEN COLDER THAN THAT ACROSS THE ENTIRE STATE. >> THE GOVERNOR THERE IN NEW HAMPSHIRE, OF COURSE, AUTHORITIES IN BOSTON WARNING OF THIS, AS WELL. ROB WITH US TONIGHT ON THIS VERY SERIOUS COLD MOVING IN. HEY, ROB. >> Reporter: HI, DAVID. THIS IS INDEED LIFE-THREATENING COLD. THE ACTUAL FRONT IS PUSHING ACROSS THE BORDER. YOU SEE IT HERE. IT'S KIND OF BEING DRAGGED ALONG BY THAT WAVE OF RAIN THAT BROUGHT ALL THAT ICING TO THE SOUTH. THAT'S FINALLY MOVING OFF INTO THE ATLANTIC. A LITTLE BIT OF SNOW SQUALLS TONIGHT, MIGHT SEE AN INCH OF SNOW, BUT BLIZZARD WARNINGS UP FOR NORTHERN MAINE, NOT BECAUSE OF HEAVY SNOW, BUT BLOWING SNOW. THE SUB-ZERO STUFF GOING TO TURN THAT SNOW INTO A FINE DUST AND BE BLINDING AT TIMES. SATURDAY MORNING, WIDESPREAD COLD FROM ALBANY BACK THROUGH INDIANAPOLIS BACK THROUGH OMAHA, BUT IT'S SATURDAY MORNING WHERE THE REAL COLD STUFF COMES IN. 60 BELOW, THAT WOULD BE AN ALL-TIME RECORD IN CARIBOU, BUT LOOKING AT MINUS 9 FOR A WIND CHILL IN NEW YORK. MINUS 34 IN BOSTON. 36 BELOW IN BURLINGTON. THAT WILL GIVE YOU FROSTBITE IN LESS THAN TEN MINUTES. STAY INSIDE IF YOU CAN, OR COVER UP IF YOU HAVE TO GO OUT. DAVID? >> YEAH, TAKE THIS SERIOUSLY FOR SURE.