doc_text: Typhoon Yunya, packing 80 mph winds, slammed into the eastern coast of Luzon island, which includes Mount Pinatubo, early in the day.
  But it quickly weakened to a tropical storm with 60 mph winds by the time it was centered about 70 miles east of the volcano.;
  Still, heavy rains churned up by the typhoon drenched Manila and the provinces near the volcano, raising fears of mudflows that could bury whole towns up to 25 miles away.;
  Meanwhile, President Corazon Aquino dismissed a British newspaper report that Americans had warned her of possible radioactive contamination if the volcano damages nuclear storage sites at Clark Air Base, abandoned Monday by nearly 15,000 Americans.; The U.S. military began flying home hundreds of the 28,000 Americans who crowded onto Subic Bay Naval Base as a bizarre tropical blizzard of thick volcanic ash caused power failures across the base Friday during a third day of increasingly violent eruptions of Mount Pinatubo.; Showers of 'mud drops'; "It looks like it's snowing outside," said military spokeswoman Capt.
  Kim Urie.
  Headlights and street lamps were turned on at midafternoon as a "dark, black cloud" passed over the giant Navy base and dropped a gritty rain of "mud drops," she said.
  ; At least four people have died, 24 have been hurt and four have been listed as missing since Pinatubo began erupting Sunday, after lying dormant for six centuries, officials said.
  About 84,000 people, including Americans, have been evacuated.; Police said 12 people had been arrested for looting at Clark.; Five explosions shook the mountain early today, showering ash over a wide area and providing a spectacular pre-dawn display of nature's fireworks against a backdrop of lightning and rain.; Friday, eight thunderous explosions shot a cloud of ash and steam nearly 19 miles high.; Friday's eruptions hurled ash over Clark, 10 miles east of the volcano, and Subic, 25 miles southwest, where the Clark personnel had been temporarily housed.
  Gray ash also fell in Manila, 60 miles south.
  ; At Subic, base spokesman Robert Coble said generators had to be shut down from time to time to clean out volcanic ash, plunging the base into darkness.;
  River temperatures rising; Temperatures in local rivers were rising because of the volcanic debris, officials said.; After sunset, the volcano spewed two streams of orange, glowing material from its crater in what scientists thought was the first appearance of lava during the weeklong eruptions.;
  Raymundo Punongbayan, director of the Philippine Institute of Vulcanology and Seismology, said Friday's blasts were part of a single eruption, the largest since Mount Pinatubo awoke Sunday from its 600-year slumber.;
  A British newspaper, the Guardian, reported Thursday that the Americans declared a nuclear alert at Clark late Wednesday and informed governments in Manila and Hong Kong that "a nuclear accident in the region was possible."
  But Aquino told reporters the story was "baseless and purely fabricated."; The United States refuses to confirm or deny that it stores nuclear weapons in the Philippines.; Foreign Secretary Raul Manglapus also said the eruption should have no effect on talks on the future of Clark and Subic, where leases expire Sept. 16.
  The talks are deadlocked over compensation and the duration of a new agreement.; Punongbayan said Mount Pinatubo could remain active for years if it follows the pattern of similar Philippine volcanoes.
  That would leave Clark unusable.
summary_text: Mount Pinatubo continues to be wracked by increasingly violent eruptions as Typhoon YUNYA slammed into the eastern coast of Luzon, Philippine Islands.
  The two forces of nature threaten to engulf cities and towns in their path.
  Temperatures of rivers were rising due to hot ash.
  Debris was clogging everything including generators, thus disrupting power supplies.
  Pinatubo began erupting violently on Friday and these explosions are seen as a single eruption.
  The eruption is occurring at the same time as U.S.- Philippine discussions on a military bases treaty.
  Pinatubo could remain active for years, possibly rendering Clark inoperable.