This year will be the first full moon to occur on the winter
  solstice, Dec. 22, commonly called the first day of winter. Since a
  full moon on the winter solstice occurs in conjunction with a lunar
perigee
  (point in the moon's orbit that is closest to Earth), the moon will
  appear about 14% larger than it does at apogee (the point in it's
elliptical
  orbit that is farthest from the Earth).

  Since the Earth is also several million miles closer to the sun at
this
time of the year than in the
  summer, sunlight striking the moon is about 7% stronger making it
  brighter. Also, this will be the closest perigee of the Moon of the
  year since the moon's orbit is constantly nutating.

  If the weather is clear and there happens to be a snow cover where you

  live, the ambient light level will be very high.

  On 21 Dec 1866, the Lakota Sioux took advantage of this combination
  of occurrences and staged a devastating ambush on soldiers in the
  Wyoming Territory.

  In laymen's terms it will be a super bright full moon, much brighter
  than usual AND it hasn't happened this way for 133 years!
  Our ancestors 133 years ago saw this. Our descendants 100 or so
  years from now will see it again.