The low water levels along the Mississippi River are exposing seldom-seen sandbars. But river experts are urging people to stay clear of what is often essentially quicksand.  People boating and fishing sometimes stop along sandbars since they may look like an enticing beach area.  But Memphis Army Corps emergency management chief Steve Barry tells KZIM KSIM the drought-exposed sand along rivers has been below the surface so long that it is saturated mud.  Barry says combine that with the swift undercurrent of the water, even with a low River level, and it creates a dangerous situation.  Earlier this month, an 11-year-old girl had to be rescued after sand swallowed her up to her waist while she and her family fished along the Mississippi near New Madrid.  The River is forecast to stay near the 7 to 8-feet level in Cape through next Wednesday.