1970 Pacific typhoon season

Typhoon Nancy (Atang)

Typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	February 19 – February 28
Peak intensity	220 km/h (140 mph) (1-min)  950 hPa (mbar)

Nancy originated from the interaction between an active ITCZ and a cold front near the Caroline Islands and the equator in mid February. An increase in convection was shown by weather satellites on February 18 and by the following day a recon aircraft found a weak depression to the south of the Caroline Islands. The depression moved west, suppressed south by a high pressure ridge to the north, and gradually strengthened into a tropical storm and was given the name Nancy early on February 20. Nancy became a typhoon on the 22 about 100 miles northwest from Woleai. On February 23 Nancy passed to the north of Yap where strong gale winds occurred. Continuing to encounter more favorable conditions Nancy was able to achieve a peak intensity of 140 mph (220 km/h) and a pressure of 952 hPa (28.1 inHg) on February 24.^[1] This was the equivalent of a category four hurricane. It is rare to have a typhoon of this magnitude during the month of February, as noted by the JTWC, only Irma of the 1953 season reached the same intensity at the time. As Nancy approached the Philippine Islands the typhoon traversed to the western ambit of the ridge that had kept it to the south, allowing it to move farther in a north direction. During the 25 Nancy passed east off the coast of the easternmost islands of the Philippines. On the island of Catanduanes, the edge of the eye brushed the eastern coast. A U. S. Coast Guard loran station on Catanduanes recorded intense winds, at which point the equipment malfunctioned. The storm encountered a hostile environment to the northeast of Luzon and began to weaken. By February 26 Nancy had become a tropical storm and shortly afterward had transitioned into an extra tropical cyclone and moved off into open ocean. By the 28 what remained of Nancy was a frontal trough.^[2]

Nancy caused significant damage to the Philippines and surrounding islands. Particularly hard hit were the islands of Catanduanes and Samar. Damage was estimated near a million dollars with 5,000 families homeless. On the Island of Yap heavy storm surge caused $160,000 in damages, luckily no one was killed. A 6,065 ton American ship, Antinous, encountered the full brunt of the typhoon shortly before midnight, February 24. Ship logs record sea swells of over 40 feet, winds over 100 knots, a central pressure of 953 millibars, and three of the ships large butane tanks on the main dock broke free during the storm along with a portion of its bulwark.^[2]

CMA Tropical Depression Two

Tropical depression (CMA)
Duration	March 15 – March 17
Peak intensity	35 km/h (25 mph) (10-min)  1004 hPa (mbar)

On March 14 the CMA started to track an area of disturbed weather east of Yap. It moved in a northwest direction before tracking over Yap on March 15 at which point it had become a tropical depression. Continuing to track in a northwest direction it eventually reached a peak intensity of 25 mph (40 km/h) and a pressure of 1,004 hPa (29.6 inHg) on March 16. Late on March 17 the depression moved into the Philippines.^[3]

CMA Tropical Storm 03

Tropical storm (CMA)
Duration	June 11 – June 16
Peak intensity	75 km/h (45 mph) (10-min)  992 hPa (mbar)

On June 11 the CMA began tracking a tropical depression in the South China Sea, west of Luzon. The depression moved northeast toward Taiwan. Early on June 13 the HKO started to track the depression while the CMA had upgraded it into a tropical storm. Not long after, the storm passed over Taiwan and weakened back to a depression. It regained strength on June 14, while the HKO stopped tracking it, the CMA continued to monitor its intensification. By midday it reached a peak strength of 45 mph (75 km/h) and a pressure of 992 hPa (29.3 inHg) while located to the south of the Korean Peninsula. The tropical storm passed over the island of Jeju and brushed the southern tip of South Korea. While in the Yellow Sea the storm weakened back to a depression and sharply curved toward Shandong before dissipating on June 16.^[4]

Tropical Depression Bising

Tropical depression (PAGASA)
Duration	June 13 – June 17
Peak intensity	55 km/h (35 mph) (10-min)  1000 hPa (mbar)

The CMA tracked a weak depression in the South China Sea a few days following Tropical Storm Three. It took a similar track to the east-northeast toward Luzon. It reached a peak intensity of 35 mph (55 km/h) and a pressure of 1,000 hPa (30 inHg) on June 15. It took a turn to the northwest off the coast of Taiwan which then brought it inland. It dissipated on June 17 north of Taiwan.^[5]

CMA Tropical Depression Five

Tropical depression (CMA)
Duration	June 20 – June 22
Peak intensity	35 km/h (25 mph) (10-min)  1002 hPa (mbar)

Following a string of storms in the South China Sea another depression formed on June 20. It moved north-northwest, reaching a peak of 25 mph (40 km/h) and a pressure of 1,002 hPa (29.6 inHg), before making landfall on Hainan. It took a curved path in the Gulf of Tonkin which lead it to make its second landfall in Vietnam.^[6]

Typhoon Olga (Deling)

Typhoon (JMA)
Category 5 super typhoon (SSHWS)
Duration	June 27 – July 5
Peak intensity	260 km/h (160 mph) (1-min)  905 hPa (mbar)

In mid-June a change in the jet stream over a large part of the Pacific Ocean caused an increase in tropical wave frequency. One of these waves would become the precursor to Olga. The wave was first noticed near the Marshall Islands, particularly the Island of Majuro on June 24. As it moved west weather satellites depicted the wave had begun to organize with considerable convection and spiraling storm bands as it neared the Central Caroline Islands. Due to the waves close proximity to a high pressure area to the north, strong easterlies accelerated it to the west. The increased forward speed inhibited the establishment of a circulation until it was south of Guam early on June 29, though the JMA had classified it a tropical depression two days earlier. Later that day reconnaissance had detected a closed center and gale force winds and the low was upgraded to a tropical storm and was given the name Olga. As it entered the Philippine Sea the ridge that had kept it to the south began to weaken allowing Olga to move in a northwestward direction. Moving into an increasingly favorable environment, the storm slowed in its forward speed, and strengthened into a typhoon late on June 29. Rapid intensification followed as the system bottomed out at a pressure of 906 hPa (26.8 inHg) and winds of 160 mph (260 km/h) on July 1.^[7] The strengthening happened within a little over a day brought it to a super typhoon, the first of the season. The 62 millibar drop with the day of June 30 and July 1 caused a very high wind profile around the six mile radius eye. The storm followed a break in the ridge and moved northward while weakening gradually. While passing to the east of Taiwan a short wave from the Chinese mainland caused a sharp direction change in Olga's path. A low developed in the wake of the short wave, dominated Olga causing the typhoon to greatly weaken. Dry air soon entered the circulation caused a shallowing in the systems overall convection. By July 5 Olga made landfall on the Kansai region, south of Osaka, as a tropical storm. The system continued into the Sea of Japan, and became merged within a cold front. The remaining low tracked over South Korea before completely dissipating on July 7.^[2]

Olga was a very intense typhoon, causing an estimated ten million dollars to Japan alone. While passing through the Ryukyu Islands wind measurement were as high as 130 mph (205 km/h) as it passed 50 miles to the west on July 4. Heavy rains occurred over Japan, up to 14 inches, caused landslides and extensive flooding in some areas, as well as in South Korea. In Japan 20 fatalities were recorded and in South Korea 29 were recorded due to the extreme rainfall.^[2]

Severe Tropical Storm Pamela (Klaring)

Severe tropical storm (JMA)
Tropical Storm (SSHWS)
Duration	June 28 – July 1
Peak intensity	95 km/h (60 mph) (1-min)  980 hPa (mbar)

Severe Tropical Storm Ruby (Emang)

Severe tropical storm (JMA)
Tropical Storm (SSHWS)
Duration	July 11 – July 17
Peak intensity	100 km/h (65 mph) (1-min)  985 hPa (mbar)

Tropical Storm Sally

Tropical Storm (JMA)
Tropical Storm (SSHWS)
Duration	July 19 – July 23
Peak intensity	75 km/h (45 mph) (1-min)  992 hPa (mbar)

Tropical Storm Therese

Tropical Storm (JMA)
Tropical Storm (SSHWS)
Duration	August 1 – August 4
Peak intensity	75 km/h (45 mph) (1-min)  990 hPa (mbar)

Tropical Storm Violet (Heling)

Tropical Storm (JMA)
Tropical Storm (SSHWS)
Duration	August 3 – August 9
Peak intensity	75 km/h (45 mph) (1-min)  992 hPa (mbar)

Typhoon Wilda (Iliang)

Typhoon (JMA)
Category 3 typhoon (SSHWS)
Duration	August 9 – August 15
Peak intensity	195 km/h (120 mph) (1-min)  940 hPa (mbar)

A broad surface trough developed into Tropical Storm Wilda on August 9. After drifting to the west-southwest, it turned to the north, where it reached a peak of 120 mph winds on the 12th near Okinawa. Wilda continued northward, and weakened slightly to a 105 mph typhoon before making landfall on western Kyūshū on the 14th. Wilda accelerated to the northeast, and became extratropical on the 15th. The typhoon caused heavy rain, killing 11 people.

Typhoon Anita

Typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	August 15 – August 22
Peak intensity	250 km/h (155 mph) (1-min)  910 hPa (mbar)

An upper level low contributed to the formation of Tropical Depression 11W on August 16 over the northern Marianas Islands. It quickly intensified, reaching typhoon status that night. Anita's intensification rate slowed initially, but as it continued northwestward late on the 18th and 19th, Anita rapidly strengthened to a 155 mph super typhoon. It weakened as it accelerated to the north-northwest, and hit western Shikoku in Japan on the 21st as a 115 mph typhoon. Anita, which became extratropical on the 22nd, caused 23 deaths and sank 31 vessels.

Typhoon Billie (Loleng)

Typhoon (JMA)
Category 3 typhoon (SSHWS)
Duration	August 21 – August 31
Peak intensity	205 km/h (125 mph) (1-min)  945 hPa (mbar)

Typhoon Clara

Typhoon (JMA)
Category 2 typhoon (SSHWS)
Duration	August 25 – September 4
Peak intensity	155 km/h (100 mph) (1-min)  960 hPa (mbar)

Tropical Storm Clara developed on August 26 southeast of Japan from an upper tropospheric circulation that separated from the Mid-Pacific trough. It quickly strengthened, and became a typhoon on the 27th at 31.9º North, one of only 16 Western Pacific typhoons to reach that strength north of 30ºN. Clara peaked at 95 mph before coming close to Japan, when a shortwave trough forced it sharply eastward. The storm maintained its intensity until becoming extratropical on September 3. An interesting fact about Clara was a reconnaissance mission flown into Hurricane Dot in the central Pacific also flew into Clara on the same flight, an unusual accomplishment not normally seen.

Tropical Storm Ellen (Norming)

Tropical Storm (JMA)
Tropical Storm (SSHWS)
Duration	September 3 – September 6
Peak intensity	85 km/h (50 mph) (1-min)  985 hPa (mbar)

Severe Tropical Storm Fran (Oyang)

Severe tropical storm (JMA)
Tropical Storm (SSHWS)
Duration	September 3 – September 10
Peak intensity	100 km/h (65 mph) (1-min)  975 hPa (mbar)

Typhoon Georgia (Pitang)

Typhoon (JMA)
Category 5 super typhoon (SSHWS)
Duration	September 7 – September 16
Peak intensity	260 km/h (160 mph) (1-min)  905 hPa (mbar)

On September 11, Super Typhoon Georgia, which formed on the 8th, struck northern Luzon with winds of 160 mph. It weakened over the island, turned to the northwest, and hit southern China as a strong tropical storm on the 13th. Georgia produced little rain over the Philippines, but its strong winds caused 95 casualties (with 80 missing) and damage at $1.4 million (1970 USD).

Typhoon Hope

Typhoon (JMA)
Category 5 super typhoon (SSHWS)
Duration	September 19 – September 30
Peak intensity	280 km/h (175 mph) (1-min)  895 hPa (mbar)

The strongest storm of the season, Hope was a very strong category 5 super typhoon with pressure reaching 895 mbar. Hope did not affect land and stayed well out to sea. It formed in September 19 and dissipated on September 30.

Tropical Depression Ruping

Tropical depression (PAGASA)
Duration	September 21 – September 25
Peak intensity	55 km/h (35 mph) (10-min)

Typhoon Iris

Typhoon (JMA)
Category 3 typhoon (SSHWS)
Duration	October 2 – October 8
Peak intensity	185 km/h (115 mph) (1-min)  960 hPa (mbar)

Typhoon Joan (Sening)

Typhoon (JMA)
Category 5 super typhoon (SSHWS)
Duration	October 9 – October 18
Peak intensity	280 km/h (175 mph) (1-min)  905 hPa (mbar)

A tropical disturbance organized into Tropical Storm Joan on October 10, east of the Philippines. Conditions favored strengthening, and Joan reached typhoon status on the 11th. From late on the 11th to early on the 13th, Typhoon Joan rapidly intensified to a 175 mph Super Typhoon. It struck the southeastern Luzon at that intensity on the 13th, and crossed the archipelago. After weakening to a minimal typhoon, Joan turned to the northwest, where it reintensified to a 115 mph typhoon. It made landfall on eastern Hainan Island on the 16th, and dissipated on the 18th over China. Joan left 768 people dead (with 193 missing), and caused $74 million in damage (1970 USD), mostly from agricultural losses.

Typhoon Kate (Titang)

Typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	October 14 – October 26
Peak intensity	240 km/h (150 mph) (1-min)  940 hPa (mbar)

Tropical Storm Kate developed just behind Typhoon Joan, east of the southern Philippines on October 14. It tracked westward as a small cyclone, and strengthened into a typhoon on the 15th. It made landfall twice, once in the Philippines and once in Vietnam, resulting in at least 631 fatalities (with 284 missing) and $50 million in damage.

Typhoon Louise

Typhoon (JMA)
Tropical Storm (SSHWS)
Duration	October 23 – October 29
Peak intensity	110 km/h (70 mph) (1-min)  990 hPa (mbar)

Severe Tropical Storm Marge (Uding)

Severe tropical storm (JMA)
Tropical Storm (SSHWS)
Duration	October 27 – November 8
Peak intensity	100 km/h (65 mph) (1-min)  990 hPa (mbar)

Tropical Storm Nora

Tropical Storm (JMA)
Tropical Storm (SSHWS)
Duration	November 1 – November 4
Peak intensity	95 km/h (60 mph) (1-min)  1000 hPa (mbar)

The remnants of Tropical Storm Nora contributed to the formation of the 1970 Bhola cyclone which devastated Bangladesh.

Severe Tropical Storm Opal

Severe tropical storm (JMA)
Tropical Storm (SSHWS)
Duration	November 11 – November 17
Peak intensity	95 km/h (60 mph) (1-min)  990 hPa (mbar)

Typhoon Patsy (Yoling)

Typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	November 14 – November 22
Peak intensity	250 km/h (155 mph) (1-min)  910 hPa (mbar)

A tropical disturbance organized into Tropical Depression 27W on November 14 near the Marianas Islands. A strong ridge to its north forced it westward, where it strengthened to tropical storm status later on the 14th. Patsy steadily intensified, reaching typhoon strength on the 16th and peaking at 155 mph on the 18th. Its inflow became disrupted by the Philippines to its west, and Patsy hit Luzon on the 19th with winds of 130 mph, making it the 3rd strong typhoon since September to strike the island. After crossing the island, Patsy traversed the South China Sea, where cooler waters kept the system a tropical storm. On November 22, Patsy struck Vietnam, and dissipated soon after. Typhoon Patsy was one of the deadliest typhoons to strike the Philippines in its history. 611 people were killed (with 351 missing) on the island, and 135 people were killed at sea due to shipping failures. Because the Vietnam War was raging at that time, its difficult to say about the damage or death toll, but estimates say that 30 people died in Vietnam.

Tropical Depression Aning

Tropical depression (PAGASA)
Duration	November 24 – November 25
Peak intensity	55 km/h (35 mph) (10-min)

Tropical Storm Ruth

Tropical Storm (JMA)
Tropical Storm (SSHWS)
Duration	November 26 – November 29
Peak intensity	75 km/h (45 mph) (1-min)  996 hPa (mbar)

Tropical Depression Bidang

Tropical depression (PAGASA)
Duration	December 17 – December 17
Peak intensity	55 km/h (35 mph) (10-min)

Other systems

According to the Japan Meteorological Agency, on September 2 Tropical Cyclone Dot briefly crossed the International Date Line from the central Pacific into its area of responsibility, crossing back later that day.^[8]

Philippines

The Philippine Atmospheric, Geophysical and Astronomical Services Administration uses its own naming scheme for tropical cyclones in their area of responsibility. PAGASA assigns names to tropical depressions that form within their area of responsibility and any tropical cyclone that might move into their area of responsibility. Should the list of names for a given year prove to be insufficient, names are taken from an auxiliary list, the first 6 of which are published each year before the season starts. Names not retired from this list will be used again in the 1974 season. This is the same list used for the 1966 season. PAGASA uses its own naming scheme that starts in the Filipino alphabet, with names of Filipino female names ending with "ng" (A, B, K, D, etc.). Names that were not assigned/going to use are marked in gray.

Retirement

Due to an extreme impact in the Philippines, PAGASA later retired the names Pitang, Sening, Titang, and Yoling and replaced by Pasing, Susang, Tering, and Yaning for the 1974 season. This season has the most retired names by PAGASA at that time.