a bright tube of light resembling an elevator shaft descended from the light object to the ground and then returned.

We were traveling south on County A21 approximately 2 miles north of Intersection with California 36 when an extremely bright light appeared to west of our location at what appeared to be only 2-300 feet above the tree tops.  This light was stationary and what appeared to be a tube of light began decending towards the ground.  It took approximately 10 minutes to reach the ground and the tube was visible from the light above the trees to the ground and could be described as an elevator shaft.  After the 10 minutes or so it began to ascend again towards the bright light in the sky, just as if the elevator was returning to the top of the shaft.  the tube of light began to disappear from the ground traveling upwards toward the bright light in the sky.  This tube seemed to be about 10 to 20 feet in diameter.  When the lighted tube collapsed at the bright light at top, a very large cloud of steam or smoke appeared and began drifting south west at about 5-10 miles per hour.  We had all gotten out of the car to observe this and returned to the car and followed this cloud for about 5-7 miles where we saw a sheriffs car with two deputies standing beside the can.  We stopped and asked if they had seen the same as we and they replied that they had seen the drifting smoke and were looking for the source.  We did not tell them of the tube of light so as to not be embarrassed.
Date is approximate.  PD