"There was no snowstorm": New investigation conclusions on the weather the night of the Dyatlov Pass incident

In the winter of 1959, a group of nine hikers disappeared in the mountains of the Northern Urals. They were led by fifth-year student of the Ural Polytechnic Institute Igor Dyatlov. For 18 days, the group had to ski 300 kilometers in the north of the Sverdlovsk region, climbing two peaks. The hike was of the highest category of difficulty according to the 1950s classification. A month after the disappearance of the hikers, rescuers found their tent cut from inside and five frozen bodies within a radius of one and a half kilometers on the slope of a pass. The bodies of the rest were found only in May. The investigation found that some of the hikers died from the cold, but some of them had fatal injuries of unknown origin. What exactly happened to the Dyatlov group is still unknown.

In 1959, investigators closed the criminal case with a strange wording: "The cause of death of hikers was a overwhelming force, which they were unable to overcome." No one ventured to explain what kind of "overwhelming force". The first thing that comes to mind is maybe some kind of meteorological phenomenon? Like a sbowstorm? But there is practically no mention of the weather in the official documents. No requests to local hydrometeorological services, no meteorological information. In general, we doubt that the investigators were then interested in the weather on the day the hikers died.

In the criminal case, there are only a few witness statements, from which it is known that, for example, the forester Rempel from Vizhay warned Igor Dyatlov about strong winds in the mountains in winter. And witness Popov said that in early February the weather was terribly windy. But the forester's warnings can hardly be considered official confirmation, and Popov, judging by the document, communicated with the investigator on February 6, which does not fit in with the beginning of the criminal case initiated on February 26.

As it happens, no one has yet explained this discrepancy in the dates, not even the prosecutor's office. But the prosecutor's office tried to establish whether there was a severe frost and winds with the force of a hurricane at the pass on the night of 1 to 2 of February, 1959.

A microclimatic examination of the Kholat Syakhl mountain region in January-February 1959 was carried out at the Voeikov Main Geophysical Observatory in St. Petersburg. The specialists used the method of calculating weather conditions based on data from several weather stations. In our case, expert Galina Pigoltsina determined a detailed microclimatic assessment of the Dyatlov pass, relying on the readings of January-February 1959 of the nearest stations Ivdel, Burmantovo, Vizhay, as well as Taganay (a high-mountain point 600 km south of Kholat Syakhl), Polyudova Kamen (western foothills of the Urals ). The expert noted that the Dyatlov pass has been studied "in meteorological terms extremely insufficiently", and information about the area is "practically absent". That is why the conclusions are circumstantial. Here they are:

Temperature

It snowed continuously in the area of Mount Kholat Syakhl from January 31 to February 1. The snowfalls were accompanied by strong winds, with temperatures ranging from -10°C to -32°C. Please note that temperatures are calculated not only by hours and by hiker's locations.

Temperatures in °F

The well-known forensic expert Eduard Tumanov does not agree with this conclusion.

- I do not agree with the method of calculating the time of death by examining the stomach content, the expert says. - It is based on the fact that a person ate at a certain hour and the contents gradually enter the stomach, and then descend into the intestines, and that all this happens at some intervals. But each person has his own intestinal rhythm. And in the case of Dyatlov group incident, cold and stress must be taken into account. And even the cause of death affects intestinal motility. The reaction of the intestines to agony can not be predicted and taken into account e.g. each body reacts differently.

Wind

Was there a strong wind (with force of a hurricane) on Kholat Syakhl that drove the hikers out of their tent to their demise? We know from ourselves that a strong piercing wind blows constantly on the mountain - both in winter and in summer. The microclimatic examination answers the questions how strong it was on February 1, 1959.

Galina Pigoltsina claims that on February 1 and 2, 1959, according to aerological and synoptic data, a northwest wind was blowing over the mountains. A wind shadow has formed on the eastern slope (a place where the wind speed is significantly reduced). Skiers set up their tent there.

Wind speed in mph

It turns out that the wind speed was relatively low. There was no snowstorm in the day of the Dyatlov group incident. We found an circumstantial confirmation of this in the diaries of journalist Gennadiy Grigoriev "Snowstorm in the Mountains", who was at the scene of the tragedy during the search. He wrote: "I imagined, listening to the whisper from the cedar, how Krivonischenko and Doroshenko died here. There is moss on the birch trees. Near the cedar there is a mountain ash [aka rowan] bush. Snow all around (deep). On the mountain ash are a few dry leafs and a some berries not yet pecked by the birds." Obviously, a hurricane wind would not have left any leaves or berries on the trees.

Wind chill temperature index

The "feels like" temperature is a measurement of how hot or cold it really feels like outside. For example, skin that is exposed to wind and cold temperatures will make a person feel that it is colder outside than it really is because heat is drawn away from the body at a faster rate. When we look at the weather on the phone, the application shows two values: minus 25, it feels like minus 30. The latter value is the wind chill index, the complex effect of temperature and wind on a person.

The wind chill index on 1 and 2 of February, 1959, at the tent and cedar:

Wind chill temperature index in °F

Wind chill index values:

It turns out that at the moment when the tourists left the tent (at about 9 pm), the wind chill index both at the level of the tent -31.8°C (-25.2°F) and at the level of the cedar -29°C (-20.2°F) corresponded to the moderate risk of hypothermia and frostbite... By the time three hikers decided to scale the slope back to the tent, at about 3~5 am, the wind chill index at the cedar was already -43~-46°C (-45.6~-50.8°F).

Snow

The key point of the microclimatic examination is the increased thickness of the snow cover to 250 cm, which, according to Pigoltsina, formed 50 m above the tent. It was this large mass of snow that allegedly descended onto the tent under the influence of the wind and thaw. It is known that at the end of January the weather in those parts was warm for the winter. But on February 1, the temperature began to drop lower and lower. This, according to some researchers, provoked the formation of the snow slab.

A participant in the search for the Dyatlov group, Vladislav Karelin, analyzed the expert's calculations and did not agree with them.

- I was at the pass from February 27 to March 9, 1959, - Vladislav Georgievich recalls. - And I didn't see any signs of an avalanche. In addition, the tent was not on the eastern slope of Kholat Syakhl, but on the slope of the northeastern spur of this mountain range. The expert calculated the distribution of the height of the snow cover over the tent, using the pattern she obtained on the slopes of the Aibga ridge in the Caucasus. But the conditions of the Caucasian relief are fundamentally different from the altitude characteristics of the Ural Mountains. The slopes and peaks in the Caucasus are steep and rocky, with a well pronounced prominence, and in the Urals there are smooth outlines of peaks with a small difference in heights on the slopes. These differences cast doubt on the results of the expert's calculations. In addition, my observations made during the search clearly contradict the calculated data of the expert. According to Galina Pigoltsina, the depth of the snow near the tent was 150 cm. But during my searches in February-March 1959, I repeatedly stuck a metal probe into the snow, which went deep near the tent in no way more than 80-100 cm. According to the expert's calculations, the depth of the snow on the northeastern spur of Mount Kholat Syakhl in 1959 was 140 cm. But I, together with the head of search operation Evgeniy Maslennikov, climbed the northeastern spur. And there I saw stones, slightly powdered with snow. Therefore, I have great doubts about the calculations and conclusions made by the expert.

"The avalanche could have happened with a high degree of probability," the expert concluded. But it is obvious that the possibility of an avalanche is not evidence of its actual occurance. In addition, the expert did not give any real and specific signs of an avalanche. Therefore, it is not yet possible to speak of the avalanche version as the only possible cause of the tragedy.