TOKYO, Aug 15 (Reuters) - Nearly 800 flights were cancelled and tens of thousands of homes lost power as a slow-moving typhoon made landfall in western Japan early on Tuesday, prompting authorities to issue flood and landslide warnings.

Approaching from the Pacific Ocean, Typhoon Lan made landfall at the southern tip of Wakayama prefecture, some 400km (250 miles) southwest of Tokyo.

The typhoon, which followed closely on the heels of Typhoon Khanun during Japan's peak Obon holiday season, lashed wide swathes of central and western Japan with heavy rain and powerful winds.

Television footage showed rivers gushing and on the verge of bursting their banks. Homes and stores suffered water damage to their floors, and in Nara city, strong winds had felled scaffolding at a construction site.

Power outages hit almost 90,000 households in central and western Japan, according to regional utilities. Seven & i (3382.T) said some 210 7-Eleven convenience store outlets were shuttered to ensure safety.

The dangerous levels of rains and winds forced road closures and dozens of train lines to suspend services in the area.

Over the next 24 hours, the central Tokai region - home of Toyota Motor (7203.T) - was expected to get about 350 mm (13.8 inches) of rainfall, nearly three times the average rainfall for the month of August. Many factories close during the Obon holidays, when city-dwellers return to their ancestral homes.

Typhoon Lan had sustained winds of 150 kph (93 mph) and was moving northwest across the western part of the main island of Honshu at around 15 kph (9 mph). It was forecast to reach the Sea of Japan by early Wednesday and continue north along the sea, according to Japan's weather agency.