Fire damage to a Universal Orlando attraction is so extensive that arson investigators are unable to determine the cause of the blaze, authorities said this afternoon.

But the Orlando Fire Department nonetheless said the fire, which erupted Saturday afternoon in the roof of Dudley Do-Right's Ripsaw Falls, "appears to be accidental."

The investigation is still active.

Universal has said that Ripsaw Falls will remain closed several weeks while it repairs the attraction and performs other seasonal maintenance. The fire, which produced thick, black smoke that could be soon all around Islands of Adventure, forced the resort to briefly close all of Toon Lagoon, one of six themed "islands" that make up the theme park.