Swift currents and a swelling Mississippi River — which is beginning its slow crest in Vicksburg today at 42.8 feet — have led the waterborne American Wind Symphony Orchestra to cancel a gig at Natchez and instead offer a free show at City Front at 7 p.m. on Memorial Day.

“The water coming around the bend (at Natchez) is just too strong. There was too much danger in terms of the musicians, and I decided I didn’t want to take the chance,” said Robert Boudreau, who founded the Pittsburgh-based AWSO in 1957 and remains the conductor.

The orchestra performs from a barge modified into a stage and tied off on the bank.

As of this morning, the river was running at 42.8 feet at Vicksburg — just below flood stage of 43 feet — with no change over the past 24 hours. After jacking up the forecast crest and pushing it back a handful of times last week, Lower Mississippi River Forecast Center Hydrologist Angelo Dalessandro said this morning the river has probably topped out here.