New altitude survey; Mt. Craddock, west face; Mt. Gardner, ascent; Mt. Tyree, attempt. As a continuation of previous GPS work on Mt. Shinn (2002), Livingston Island (2003), and the Vinson Massif (2004), another expedition from the Omega Foundation planned to climb and measure Mts. Tyree, Craddock, and Gardner during 2005-06. These mountains were believed to be the second, fourth and fifth highest, respectively, in Antarctica.

On November 23 we landed on a previously unvisited glacier west of Mt. Craddock and set up base camp, lower than expected, at 1,455m. During the following days we climbed a small virgin 1,978m peak to the west (via the east face and north ridge on the 24th; 500m; PD), sledged loads farther up the glacier, and made an advanced base at 2,041m, close beneath the west face of Craddock. All the team climbed the lower slopes of the face and dug a site out of a rock ridge for Camp 1 (3,258m). Steve Chaplin (U.K.) and I spent four nights there in poor weather.

December 7 was a brilliant day, and we quickly climbed the 45° snow and ice slopes of the 1,000m upper west face to reach the summit in the evening. The climbing was never difficult but sustained and sometimes on ice, so a fall would have been serious. The 2,300m route was AD. There are no flat places to put a tent, hence our excavation of the ridge.

This was the second ascent of Craddock, first climbed by Conrad Anker and Jay Smith in 1992 by a different route from the west, accessed from the glacial basin to the north of ours. Mt. Craddock has a number of high tops at its southern end but we placed the GPS on the highest rock summit, at the eastern extremity of the summit plateau, then walked back west over to a slightly higher snow dome before descending. Our Chilean teammates, Manuel Bugue- no and Camilo Rada, repeated our route next day to retrieve the GPS. Processing the data at base camp via the Australian government AUSPOS website, accessed via laptop computer and Iridium satellite phone, we determined that Craddock is in fact only 4,368m: 282m lower than the previously published official height of 4,650m.

After descending to base camp we sat out extremely bad weather,

but were finally picked up by ALE on December 17 and flown north to a new base camp, on the flat ice 5km west of Mt. Gardner. The next day we carried loads to a site for advanced base beneath Gardner’s west face, then occupied it the day after. Wanting to take advantage of the now-excellent weather, Steve and I departed the following day and climbed 2,100m to the summit in a single nine-hour push. We climbed the original 1966-67 route up a 1,200m, 45° couloir on the northwest face, followed by the long north ridge. This was the fifth ascent of this route (AD+) and the sixth overall of the mountain. The discarded food cache from the 1966 American expedition is still visible and intact near the bottom of the face, and in the couloir itself we found short lengths of old fixed rope from the same expedition. The final section of the summit ridge was severely corniced,

requiring a short bout of exposed and delicate climbing. We placed the GPS right on top. Manuel and Camilo repeated the route the following day, retrieving the GPS. This later showed that Gardner is 4,573m, 14m lower than its old official height.

In continuing good weather, we flew to the east side of the range and landed in soft, deep snow on the beautiful Patton Glacier. There, we established a base camp with marvelous views of Tyree, Gardner, Ostenso, and Evans Peak. We spent Christmas and New Year’s Eve in bad weather—cloud, fog, wind, and light snow—but managed to place a cache at the foot of the east face of Tyree. Our intended route was the Grand Couloir, first climbed in November 1997 by French alpinists Antoine Cayrol and Antoine de Choudens, from the GMHM expedition that also made the first ascents of Mt. Shear (4,050m) and Evans Peak (3,950m). One month after the French ascent, Conrad Anker and Alex Lowe summited via a slight variant on the same route, with Dave Hahn turning back up high. Tyree has not been climbed since.

We climbed a variant of the lower route, not using the couloir but going directly up the northeast ridge from its base, moving unroped with heavy packs. We placed a small tent at 3,247m in a small exposed col, where Steve Chaplin and I spent two nights. However, the condition of the couloir above was not good, with very hard ice lying under just a few centimeters of soft, sugary snow. Higher, large patches of slick blue ice were visible. These conditions, combined with incoming bad weather, led me to decide against climbing the route at this time. Two days later we descended in a whiteout to our base camp on the Patton and several days after that flew out of Antarctica.

The height order of Antarctica's highest mountains now looks like this:

Vinson Massif 4,892m

Mt. Tyree 4,852m*

Mt. Shinn 4,661m

Mt. Gardner 4,573m

Mt. Kirkpatrick 4,528m*

Mt. Elizabeth 4,480m*

Mt. Craddock 4,368m

Note: *denotes not measured by the Omega Foundation. These peaks are probably lower than the figures indicate.

The resulting data from this survey will be included on a new topographical map of the Sentinel Range, to be published later in 2006 and distributed worldwide, free of charge, in the interests of furthering knowledge of Antarctica and contributing to Antarctic science.

Damien Gildea, Australia, AAC, Omega Foundation