Hurricane John barrelled along Mexico's Pacific coast on Wednesday (August 30) as a dangerous Category 4 storm, pounding beach resorts with heavy rain and winds and blowing down trees in Acapulco. Acapulco, home to some 1 million people and a popular tourist destination, had sea surges of up to 10 feet (3.5 meters), seafront roads were ankle-deep in water and people struggled to stay on their feet in 135 mph (215 kph) winds. Emergency workers were on alert for mudslides and flash floods as John trekked parallel to the coast. Fears grew that it could make a direct hit later this week on the Baja California peninsula, popular with tourists and yachtsmen. In Manzanillo, a haven for U.S. and Canadian fishermen, people were warned the biggest sea swells and most wicked winds would hit overnight. "We know that this is a Category 4 hurricane and well, obviously, with the experience people have had in other places, we know that it is a strong hurricane and we should take all the necessary preventative measures so that this goes well and we don't have any problems," said Jose Maria Flores, of Manzanillo's Civil Protection. The Miami-based National Hurricane Center upgraded John to Category 4, the second-strongest type of hurricane, capable of extensive damage if it hits inhabited areas directly. It said John had drifted closer to the coast and could gain more strength over the next 24 hours. On its current track, John could slam into the plush resort of Los Cabos on the tip of Mexico's Baja California peninsula later this week. It is then expected to veer out into the Pacific. In October, Hurricane Wilma smashed up Cancun and other beach resorts on Mexico's Caribbean coast. It caused massive damage, sucking away large stretches of beach and stranding tens of thousands of tourists in makeshift shelters for days. A hurricane warning was in effect on Wednesday from the steel-making port of Lazaro Cardenas to Cabo Corrientes, further northwest. John was moving slowly northwest parallel to the coast about 130 miles (205 km) southeast of Manzanillo. The U.S. hurricane center said only a slight deviation would take the storm over land. Category 4 hurricanes can destroy mobile homes and seriously damage the lower floors of waterfront structures. Land lower than 10 feet (3 meters) above sea level may be flooded and require massive evacuations. Rainfall of 6 to 10 inches (15 to 25 cm), with isolated deluges of 18 inches (45 cm), were possible along the Pacific coast in the warning areas. The U.S. hurricane center warned that rain could cause flash floods and mudslides over areas of mountainous terrain.