Tropical Storm Dolphin eventually became a typhoon as it approached the Marianas during the second of May.

Hurricane (Typhoon) in ROTA, GUAM
From 14-MAY-15 12:00:00 to 16-MAY-15 00:00:00 (GST10)
Property damage: 2.00M
Crop damage: 500.00K
Reported by: Newspaper

As Typhoon Dolphin passed south of Rota, many homes on Rota were also damaged or destroyed. Numerous power lines and trees were knocked down.

Hurricane (Typhoon) in SAIPAN, GUAM
From 15-MAY-15 12:00:00 to 16-MAY-15 00:00:00 (GST10)
Property damage: 10.00K
Crop damage: 10.00K
Reported by: Official NWS Observations

As Typhoon Dolphin passed through the Marianas, it produced tropical storm force winds across Saipan. Maximum sustained winds of 39 mph with a gust to 63 mph was observed at the airport. The typhoon brought only 3.5 inches of rain to Saipan. The lowest sea level pressure recorded was 999.2 mb around 6 p.m. on the 15th.

Hurricane (Typhoon) in GUAM, GUAM
From 14-MAY-15 12:00:00 to 16-MAY-15 00:00:00 (GST10)
Property damage: 5.00M
Crop damage: 1.20M
Reported by: Newspaper

On the 15th of May, the Typhoon Dolphin approached the Mariana Islands. Typhoon Dolphin passed through the Rota Channel, just north of Guam on the night of the 15th. The southern eyewall of the typhoon passed over northern Guam. Tropical storm and typhoon force winds were experienced on Guam from the afternoon of the 15th through the morning of the 16th. The maximum sustained winds observed at Andersen Air Force Base, located on the northern part of Guam, was 84 mph. The highest gust at the Air Force Base was 106 mph.
The National Weather Service Office, located in the central part of the island recorded a maximum sustained wind of 56 mph with a peak gust of 81 mph.
The typhoon brought with it a lot of moisture, which resulted in heavy rainfall over the islands with between 12 and 14 inches of rain being observed on Guam. The heavy rain brought brief flooding in poor drainage areas and also water damage at the Guam Memorial Hospital, causing about $1.0 million damage to the hospital.
The lowest sea level pressure was 972.1 mb and was observed at Andersen Air Force Base 858Z on the 15th (around 7 p.m. on the 15th local time).
The typhoon caused disruption to the electrical power grid on Guam with 40 percent of the power customers experiencing power outages. Power to mainly northern and central Guam was affected.
There are 100 water wells on Guam with 89 backup generators to service these
wells. As only 47 of these generators were fully operational when the typhoon arrived, 3300 water customers experienced outages. Many of the backup generators experienced malfunctions. An estimated $3.0 million damage was done to utilities by the typhoon.
On Guam, 8 schools served as storm shelters. During the passage of the typhoon, the shelters held more than 1000 people. The last shelter closed on 23rd May. A reported 1055 individuals were left without a home and were given tents and canopies to live in.  Most were from the villages of Yigo and Dededo. A total of 390 homes were affected by the typhoon, with 64 destroyed or heavily damaged.
There was damage to fruit trees and other agricultural crops on Guam. An example of the damage was that done to banana crops with more than 7000 trees being damaged as the southern eyewall passed over Guam. An estimated $1.2 million worth of damage was done to crops. An additional $1.9 million damage was done to commercial businesses on the island.
A 50-foot recreational vessel broke free of its moorings during the typhoon. The Makena was moored in Apra Harbor and eventually sunk in 15 feet of water. The Makena had 1500 gallons of diesel fuel on board. Contractors successfully removed the oil and other items from the sunken vessel a few days later.
A side note to the typhoon damage was that done to a few endangered Ironwood trees. The University of Guam has a project to repopulate the island with ironwood trees. Thirty-nine of 60 trees planted were killed by the typhoon.  It was hoped that the trees would gain enough maturity to be able to produce seeds. The typhoon killed the trees before they reached this mature stage.