Satellite Detection
The impacting meteoroid was detected by both infrared and optical sensors on board US Department Of Defense satellites, which timed the terminal flares to 16:43:42 with a two second duration at 1 micron radiation.  Optical measurements showed the flash energy to be 1.1 X 10¹²J (1.1 terajoules). Bolides of H-chondrite composition have been found to have light energy conversions of order 10%.  Given the low iron content, a more realistic value for the present case is probably in the order of 5% (Nemtchinov, pers. commun.) yielding a total energy release of ~2 X 10¹³ J or ~5 kilotonnes equivalent.  This could possibly be the largest meteor impact ever recorded by satellite sensors over land. The Satellites also provided information suggesting an entry velocity of ~16 km/s. This velocity and the total estimated energy released imply this object had an entry mass somewhat in excess of 150 tonnes and an entry diameter of 5 metres.  

Eye Witness Accounts
Approximately 70 eyewitnesses of the fireball and resulting dust cloud were interviewed.  The Fireball was generally described as a multicoloured object with a tail; the only artist rendition looks much like other photographed fireballs.  The fireball produced a spectacular dust trail which was visible for ~2 hours in the local area as it drifted towards the southeast, pushed by high altitude winds.  These same clouds are believed to be responsible for a spectacular display of noctilucent clouds seen from Edmonton Alberta during evening twilight later that day (seen here).

Eye witnesses placed the duration of the fireball at ~15 seconds, which is consistent with repeat-of-actions and other indications of a slow fireball.  The brightest of the two terminal flares was described as lighting up the landscape to ten times brighter than daylight with a bluish to greenish light.  As is typical, approximately one in ten witnesses described sounds simultaneous to the fireball, which is presumed to represent an electrophonic effect.  Witnesses also often described smells associated with the fireball including both prompt and delayed effects.  Smells were frequently described as sulphurous, although hot metal and rock were also mentioned.  Prompt occurrences of smells came from distances as large as 100 km from the ground projection of the fireball. Ground shaking detonations were widely recorded by seismographs and followed the fireball by several minutes, but were generally of short duration.   

Dust Cloud / Orbit (photos here)
The singular size of this event resulted in most residents in the area being aware of it.  Many of these saw the fireball illuminated only indirectly but were soon outside to take photographs of the dust clouds that were being lit up by morning twilight (the sun was 6° below the local horizon at the time).  Photos of the dust cloud are available here.

An orbit was found with the following characteristics:
 

a (semimajor axis)	2.1 ± 0.2 AU
e (eccentricity)	0.57 ± 0.05
q (perihelion distance)	0.891 ± 0.009 AU
(argument of perihelion)	222° ± 2°
(longitude of ascending node)	297.900° ± 0.003°
i (inclination)	1.4° ± 0.9°
T (orbital period)	3.0 ± 0.4 years
DT (time since perihelion)	1072 ± 164 days
Q (aphelion distance)	3.3 ± 0.4 AU
Vinf (entry velocity)	15.8 ± 0.6 km/s

   
Meteorite recovery
On January 25 near dusk, a local resident, Jim Brook (below), found meteorites on the snow covered ice of Taku Arm of Tagish Lake while driving home.  He returned the next day to collect several dozen meteorites in total.  The meteorites represent a particularly fragile variety of carbonaceous chondrites (1, 2). The meteorites were collected without skin contact and have been kept subsequently frozen.  During the spring melt, ~500 additional meteorites were recovered from a strew field ~16 km long and ~5 km wide oriented at ~150°.  For a detailed map of the recovery area click here.