Two days later, it was upgraded into a tropical storm, and subsequently began to intensify while tracking northwest.

After turning north-northwest, the typhoon entered a period of rapid intensification and late on July 28 reached peak winds of 230 km/h (145 mph).

Typhoon Bess cut through a 400 km (250 mi) swath that included the most populated portion of Japan.

A Tropical Cyclone Formation Alert (TCFA) was issued for the easternmost system at 1900 UTC on July 21 as sea level pressures fell and convection increased within the vicinity of the disturbance.

[3][nb 2] Later on July 22, the Joint Typhoon Warning Center (JTWC) started monitoring the same system as it developed rainbands and a further increase in thunderstorm activity.

[1][3] By July 24, Typhoon Bess began to move north-northwest and slow down due to the westward building of the subtropical ridge to the north.

After performing a small loop,[1] the storm maintained its intensity until July 27, when the JMA raised the wind speed of Bess to 180 km/h (110 mph).

At 0000 UTC on July 29, according to the JMA, the typhoon attained a minimum barometric pressure of 900 mbar (27 inHg).

[3] At this time, Typhoon Bess was located 460 km (285 mi) to the southeast of Iwo Jima.

Even though the JTWC expected Bess to recurve well east of Japan within 36 hours, this did not materialize.

[3] Typhoon Bess cut through a 400 km (250 mi) swath across the most populated portions of Japan;[6] damage was reported in 30 of the 45 provinces.

[14] At the foot of Mount Fuji, a series of mudslides buried 36 vehicles, killed one person and injured five policemen.

[15] The landslides stranded approximately 2,000 persons, including 1,500 primary school children on a camping trip.

[7] In Mie, Bess was considered the worst storm to affect the city in 23 years, where 17 fatalities occurred and seven were initially listed missing.

[6] Throughout western Japan, five people were rendered missing in heavy rains that caused at least five landslides and damaged 15 automobiles.

[6] Although Tokyo was on the eastern edge of the storm, large trees were uprooted nevertheless due to high winds.

Police reports suggest that 2,857 acres (1,155 ha) of farmland were flooded, 101 bridges were washed out, and roads were damaged at 1,094 places.