I live in Yakima, and drive through Union Gap every day on my way to and from work. You can't see them from the road, but you can obviously see the containers and workers, and they have some digital signs up going both directions to "watch for rocks"..."slide area ahead".
After last winter, I am not surprised this is happening. I have never seen so much snow and ice in Yakima in a single winter. Freeze, thaw, freeze, thaw, freeze, thaw for about 4 months last year. After a good 2 feet of snow, we had ice storms, more heavy snowfall, and then temps warm enough to rain during some days, and then at night it would freeze over again. Sometimes it would then snow on top of that. Everybody noticed in the spring, as the snow finally started to melt, how it affected the roads. There were so many new potholes and cracks on most of the main roads through town it was insane. The roads looked like crap, and were even worse to drive on. I would guess that those fissures probably "started" last spring, but don't quote me on that. I am sure there are other places around the valley it is happening as well, it just turns out that these ones are close to a major freeway, along with some homes.
Driving up 410, you can still see the evidence of that recent landslide near the confluence of Rattlesnake Creek and the Naches. I think it was 6 or 7 years ago. It's amazing how the hillside just slid off. But, if you look more closely around the valley, this doesn't seem to be an uncommon occurrence. Both up 410 and 821 (Canyon Rd.), if you look up many of the draws you can see evidence of this happening throughout the ages. Some older than others, but there are many examples of it. Take the rock slides up near MM20 in the canyon for example. Those have been around for a long time, but not for ages, they are (relatively) recent. Some other larger events have happened, where you can see where the hillside slid off, but it has been long enough that trees now grow on top of them. If you look west at the Roza boat launch there is another example of one that happened long enough ago that trees are now growing on top of the slide.
Pretty cool to watch geology in action, but sucks when it threatens homes, well beings, and travel routes.
@Skip Enge - the fissures are near Union Gap, which is south of the city of Yakima, just as you start to head southwest towards the lower valley on I-82.