Season

Autumn colour, then the first snowcap

Of the 16 cameras on the Autumn Leaves page and the 16 on First Snowcap, 4 appear on both lists — cameras whose picture goes green, then red, then white. On the one at Asahidake, Daisetsuzan, the leaves peak in mid-September and the first snowcap falls on 25 September on average. That is about ten days apart.

The same camera is on both lists

This site groups cameras by subject, so you normally open either the autumn page or the first-snow page, not both. Lay the two lists on top of each other and 4 cameras turn out to be on both. What follows puts the two dates side by side for those 4. Every date here is copied from the page it links to. Nothing on this page is a season we decided ourselves.

Laid out like that, the gaps are not even, and they do not follow latitude or altitude. The two dates are decided in different ways. The autumn date is when the leaves have finished turning; the first snowcap is the day snow on the summit became visible from below. That second date depends less on whether snow fell than on whether the summit was out of the cloud that day. So there is no rule here to report — no "the further north, the shorter the gap". There are only these four numbers.

Only at Asahidake do both fall in the same month

Across all 28 cameras, Asahidake is the only place where the leaves and the first snowcap land in the same month. The autumn peaks run from mid-September to late November and the average first snowcaps from 25 September to 18 December, but every other mountain straddles a month boundary. The next earliest snowcap after Asahidake is Mount Fuji on 2 October, and from there on it is an October story.

So the Asahidake camera is a screen where green, red and white change over within September. Keep opening that one camera from mid-September into early October and you collect the changeover a frame at a time. It is a Japan Meteorological Agency camera, so the image is replaced every two minutes and you always get the same day you opened it. Bear in mind that the leaves shift by one or two weeks from year to year, and run late in years when the summer heat stays on.

Both pages say: open them in the morning

The two pages were written separately, but they say the same thing about when to watch: morning. From September to November cloud builds over the mountains before midday, so cameras shooting a summit from a distance often find it hidden by the afternoon. The colour of the leaves reads deepest, and the white of new snow separates most cleanly from black rock, at the hour when the light comes in at an angle. It is not two reasons; it is the same reason, giving the same hour.

How often the picture is replaced does differ by provider. The Meteorological Agency cameras update every two minutes, the Ministry of the Environment ones every hour — so on an Environment camera you may be looking at a frame nearly an hour old. Mountain weather turns inside an hour, so if you are waiting for a gap in the cloud, the Agency cameras suit better. When nothing comes through at all, the reasons are in What is happening when a live camera shows nothing.

The autumn-only cameras look up from lakes and plateaus

Take the 4 shared cameras out of the autumn list and the rest split cleanly by provider. The Meteorological Agency cameras point at craters and summits themselves; the Ministry of the Environment ones stand on a lake shore or a plateau and look up at the mountain. Lake Ozenuma on the Oze page, Hakka Pass above Lake Towada, the Norikura plateau on Mount Norikura, Lake Yunoko in Oku-Nikko, Renge-numa on the back side of Mount Bandai. Every one of them has water in the foreground.

With water in the frame you get the colour on the slope and the colour reflected in the lake in the same picture. Part of this group overlaps the Volcanic lakes page, and that is not a coincidence: the lakes that became autumn landmarks are mostly craters or valleys dammed by an eruption, and being ringed by mountains is exactly what gives you the view of the colour.

The latest entry on the autumn list is the Katsura River at Arashiyama, in late November. It is the only one of the 16 that is video; the rest are stills. It is the one place you see what is moving right now without waiting. The same river laid out from the outlet of Lake Biwa down to Osaka Bay is on The Yodo River System.

The snow-only cameras watch summits from a distance

The first-snow list runs the other way: more of its cameras stand back and watch only the summit. The three on Mount Fuji are at Lake Tanuki, the northern foot of Fuji and the Meteorological Agency site, all of them outside the mountain. Whether snow has settled shows in the whiteness of the outline, so there is no need to get close. Mount Iwaki, Hakkoda and Mount Iwate on The Volcanoes of Tohoku, Mount Asama, Mount Hakusan and Meakandake on Akan-Mashu are built the same way.

Fuji itself is on the first-snow list but not on the autumn list. It is a free-standing cone, and what fills the frame is bare slope and the scrub at its foot. A mountain covered in turning trees and a mountain whose new snow reads from far away are two different mountains.

The average first snowcaps span 84 days, from Asahidake on 25 September to Sakurajima on 18 December. The autumn peaks run from mid-September to late November, which is not far off the same length. What differs is where they end. On these lists, autumn stops at Arashiyama in Kyoto and the first snow carries on to Sakurajima in Kagoshima. The year-to-year shift is larger for snow, too — it can move by a month. Because the two shift by different amounts, the gap between them widens and narrows from year to year. In a year when the leaves are late at Asahidake and the snow is early, red and white land in one frame together.

Where to start

The lists themselves are Autumn Leaves and First Snowcap. Once the snow has settled in, see Snow; for cameras where steam and snow share a frame, see Geothermal Areas. Most of the 28 cameras were put there by the Meteorological Agency and the Ministry of the Environment to keep watch on volcanoes, not for sightseeing. What they are pointed at craters for is in What volcano cameras are looking at, and how the images are handled is in How we handle the camera images.