score:12
Healthy human hair can absorb 30% of its weight in water. This gal's hair weighs 25lbs when wet.
This analysis by a skeptic offers some details about average human hair. (Read the comments, too.) According to his calculations, 29 years' growth of hair (for an "average" human) could weigh that much. If Absalom was indeed unusually locked, his numbers could be even smaller.
On a side note, one human hair can support 3.5 oz, so, if the average person has 100K hairs, it wouldn't be too much for Absalom's to get tangled in a tree and hold him off the ground.