The eight of us started off at about 10.15am from Carson Pass. The weather was good although we could see lenticular clouds to the north. We made our way past Lake Winnemucca towards the slopes leading to the saddle connecting the south ridge of Roundtop to the Sisters. Stephane, Rick and Dee split off to do the Sisters and the rest of us, after a brief break to switch to axe/crampons, went towards Roundtop. There was a layer of brittle ice over the rocks below the first summit. Due to the large amounts of snow on the top of the north fork of the couloir that tops out just below the true summit, the little funky rock-step to get to the summit block was trivially hard.
After a few summit photos we quickly departed since it was getting windy and cloudy. As we were coming down from the summit, we ran into Rick, Dee and Stephane who had finished climbing the taller (northern) hump of the Sisters and were now coming up to do Roundtop as a bonus climb.
We waited for them and had lunch. By this time it got quite windy and the wind blew the snow on our faces so some of the group started going down. The snow conditions were not ideal for skiing either as there was a thin layer of powdery snow on breakable crust. Also since grooming machines no longer do Roundtop's slopes, skiing down was quite hard for me but Stephane made it look easy.
Once past Winnemucca on the way back, the weather got to be tolerable again but it had been quite bad above the lake. We were back to the cars in about six hours.