On May 21, the large eye of the typhoon crossed Guam, producing typhoon-force winds (greater than 118 km/h or 73 mph) for a period of 18 hours.

Pamela's slow motion produced 856 mm (33.7 in) of rainfall, making May 1976 the wettest month on record in Guam.

After affecting the island, the typhoon weakened and turned northeastward, passing near Iwo Jima before becoming an extratropical cyclone.

The disturbance was initially difficult to locate as it tracked generally to the south and southwest, a motion caused by a southward-moving tropical upper tropospheric trough.

On May 16, observations from Satawan in the Caroline Islands indicated that Pamela attained typhoon status, which is a tropical cyclone with maximum sustained winds of at least 118 km/h (73 mph).

[1] Upon attaining typhoon status, Pamela was a small tropical cyclone with a central dense overcast spanning 280 km (170 mi) in diameter.

After completing its counterclockwise loop, the typhoon began a slow motion to the northwest, once the ridge to its west diminished.

The typhoon steadily intensified as it began a more steady northwest movement due to a ridge to its east, and on May 19 Pamela attained peak winds of 240 km/h (150 mph) about 485 km (301 mi) southeast of Guam.

As Pamela accelerated over cooler waters and into an area of higher wind shear, it rapidly weakened and was downgraded to a tropical storm on May 25.

[1] While slowly crossing Guam, Pamela produced winds of over 185 km/h (115 mph) across the entire island over a six-hour period, causing widespread heavy damage.

As the eye was crossing the island, the winds rapidly vacillated between gusts of 150 km/h (93 mph) to calmness in the span of a few minutes; this created a large pressure gradient that caused additional damage.

One of the ships that survived in the harbor was the cutter Basswood of the Coast Guard, which recorded a wind gust of 220 km/h (140 mph).

[1] The disruption on Guam was significant enough that the JTWC's backup location at Yokota Air Base in Japan assumed forecasting and warning responsibilities for five days starting on May 20.

During the aftermath, food shortages resulted in long lines for aid at Andersen Air Force Base.

[1] Due to Pamela as well as the occurrence of other disasters in 1976, the American Red Cross went into debt,[13] after providing about $10 million in assistance to 16,000 families.

[15] On May 22, a day after the typhoon struck the island, U.S. President Gerald Ford declared Guam a major disaster area.