Yellowstone: winter was over on Friday

[Tuesday June 10, 2008] If you’re planning to head for Yellowstone National Park this week, you may be in for something of a shock – winter. This is almost mid-June after all, only a few days from the summer solstice, and at this time of year people have come to expect park roads to be open, campgrounds high and dry, and a bright warm sun shining over all.

Not this year. For almost a week now the park and most of the Greater Yellowstone Region above, say, 7,000 feet in elevation has been in the grip of what seems like October. Cold (40’s during the day 20’s at night), cloudy, and wet – showers and drizzle at lower elevations, snow that stays above 8,000 feet. Lot’s of snow. Enough snow to temporarily close the Grand Loop Highway over Mt. Washburn, the Beartooth Highway, Hayden Valley, Sylvan Pass, Craig Pass, and the South Entrance road. The Beartooth Highway, U.S. 212, from south of Red Lodge, Montana to the Wyoming state line remains closed. Avalanche danger will keep the road shut until experts determine it’s safe.

That may be a while, as weather forecasts are calling for another stiff shot of cold, rain, and snow from Monday through Thursday (June 9-12). For people visiting Yellowstone, travel through most of the geyser country in the west side of the park will be ‘normal’, if a bit cool (highs around 50) and showery. The east side may be another story. Travel over Mt. Washburn, Sylvan Pass, Craig Pass, and even Hayden Valley could be difficult between Wednesday and Thursday. There’s also residual winter snow, even in Hayden Valley, so don’t be surprised if you see snow drifts in the forests and sometimes in the open meadows.

Hayden Valley, 6/1/2008

Absaroka Mtns. near the East Entrance 6/1/2008

Actually, people shouldn’t be surprised. This ‘late spring’ is normal. That is, normal based on the weather up to about ten years ago. The early nineties were like this almost every year. In June the flow of cool and moist pacific air continues across the mid-latitudes of the U.S., including Yellowstone. Then around mid-June the flow shifts toward air coming from the Southwestern U.S., which is dryer and warmer. But Yellowstone’s weather is nothing if not variable; it’s high plateau country surrounded by mountains, which produces idiosyncratic weather patterns. If you’re traveling to Yellowstone in June, bring clothing for a wide range of conditions.

That includes short sleeve shirts, if you’re arriving this coming weekend (June 14, 15), as the forecast breaks out of the clouds, revels in the sun, and promises a multiple-day dry spell with temperatures coming back toward ‘normal’ – 60’s during the day, and 30’s at night. With a bit of luck, winter will finally be over in Yellowstone – and there won’t be sudden high temperatures that will melt all the snow in one big flood-producing whoosh.