"Day 3: From the surprisingly good Rossi Volante bivouac, we went up the WNW flank of Castor leading to a 20 - 25 meter snow climb to join the knife-edge snow ridge ti the summit. After that weather was getting worse so we called off Lyskamm and retreated to Quintino Sella refuge, where we stayed for 2 extra days waiting for the rain, hail, snow and high winds to stop..." — Christos • Aug 5, 2019

"Traversed the Castor after having climbed Pollux. We were almost struck by lightning on the descend, scary stuff. pointer: the food at the Rifugio Quintino Sella is the worst, you can not call it a meal!" — DMG • Jul 16, 2006

"The day after completing Mountain Ventures alpine training course. John Patton and I had an extra day so I led a climb with John. We took the first telepherique to Klein Matterhorn and left Klein Matterhorn at 08:00. We crossed to the Breithornpass and roped up. We then contoured round the upper slopes of the Verra glacier with some descent. Several crevasses were crossed, though there was a fairly well worn track. We passed under Pollux and made towards Zwillingjoch. Just short of this we moved on to the snow/ice slopes of Castor, first going southwards and then trending left. Moderately steep. A tricky bergschrund was crossed with a steep ice slope immediately above. I climbed this by cutting a few steps on the lowest, steepest part and then front pointing. I had run out virtually all my 100' rope before being able to belay on a rock spike. A shorter ice pitch took us to the fore peak of Castor. From there we climbed a very impressive, very narrow and delicate snow/ice arête to reach the summit of Castor. Some good views but the clouds came and went. We returned the same way. Klein Matterhorn reached 16:00. Grade PD (sup). " — peter43 • Aug 19, 1983