Climatic conditions over the territory of Russia.

2004 appeared to be generally warm in Russia. The anomaly of mean annual air temperature averaged over the territory of Russia amounted to 0.9^oC.

January 2004 was warmer then usual for most of Russia. Temperature anomalies varied from 2 to 5 ^oC. Such temperature conditions were caused by frequent intrusions of Atlantic cyclones that transported sea air to as far as Eastern Siberia and the Republic of Yakutia-Sakha. These intrusions brought abundant precipitation throughout European Russia and to some places of the Far East. In Orlov Region monthly precipitation was 2,5 times above the norm. The east of Kamchatka received 338% of the monthly precipitation norm. In Moscow the greatest amount of January snow was reported since 1891: 88 mm of monthly precipitation (210% of the norm) (Fig.1). Glaze-ice and rime deposition was reported in southern regions of Volgograd Region and the Republic of Kalmykia in the period of 1-16 January. It persisted for more than 307 hours with the maximum diameter of 138 mm in Volgograd Region and 150 mm in some places of Kalmykia

In February abundant precipitation was also experienced almost throughout European Russia, in Western and Eastern Siberia (except for the Far North), Maritime Territory and Amur Region. In Voronezh and Belgorod Regions and Krasnodar Territory monthly precipitation was almost 2.5 times above the long-term average, whereas Rostov Region received almost three monthly norms (282%). As for temperature, maximum positive anomalies were observed in Western Siberia and in the south of Eastern Siberia. In the north of Eastern Siberia a centre of cold was formed, where temperature anomalies reached -8 ^oC.

In March the centre of cold retained in the north of Western Siberia. Air temperature was below the long-term average throughout Western Siberia. In European Russia, in the south of Eastern Siberia, and in the Far East it was 2-4 ^oC warmer than usual. Against the background of positive temperature anomalies in Kamchatka monthly precipitation was 2.5 times above the norm and Krasnodar Territory received almost three monthly norms (280%) and Amur Region - three monthly norms (320%). On 27-28 March Kuriles and Kamchatka experienced the 35-40 m/s hurricane caused by the displacement of a deep cyclone.

April was cold on most of European Russia and in Western Siberia (except for Kemerovo Region and Altai Territory). A centre of cold was formed over western regions of Khanty-Mansi Autonomous Area with negative anomalies exceeding -6 ^oC. On the rest of the territory temperature was near the long-term average. In Altai Territory and Kemerovo Region rain showers persisted for three days (13-15 April). Some places received 2-3 precipitation norms. It resulted in snow-rain floods on the Upper Ob and Tom Rivers. Water level rise of up to 2.6 meters per day was reported. In some places of Kemerovo Region rivers rose 1130 meters. The breakup on the Upper Ob and Chumysh began 5 days earlier compared with the average long-term date. It was accompanied by ice jams and steep water level rise of up to 1.6-3.0 m/s.

May 2004 was very warm in Ural. In Sverdlovsk and Kurgan Regions mean monthly temperature was 4-5 ^oC above the norm. In Omsk and Krasnoyarsk the highest air temperature in the last 100 years was recorded. Hot weather was accompanied by the deficit of precipitation (10-40% of the monthly norm). It caused emergency fire hazard and triggered forest fires. Fires were recorded in Sverdlovsk and Chelyabinsk Regions and the most complicated situation was reported in Kurgan Region. May was also very warm in most of Western Siberia. In the south of Western Siberia the weather was dry and hot with daily temperature of 32-38 ^oC. In Novosibirsk Region and Altai Territory in most of the cities temperature was the highest since records began. Forest fires were reported in Novosibirsk Region, Altai Territory and the Republic of Altai.

June 2004 was marked by heavy showers in European Russia. In the first ten-day period showers with 30 mm hail were recorded in the Northern Caucasus. In Tatarstan on 1 June showers were accompanied by squally wind of 25-27 m/s. On 22 June the suburbs of Bryansk received 62 mm of precipitation in 1 hour 50 minutes. On 25 June Rostov-on-Don experienced even more intensive precipitation: it received 66 mm in 1 hour 25 minutes. Frequent and intensive rainfalls brought rain floods on rivers of the Northern Caucasus and mudflows in the mountains. Warm air coming from the North-West caused much warmer than usual weather in most of Siberia.

In July an intensive thunderstorm activity was reported in European Russia. It was accompanied by showers, squalls and hail. On 17 July hail in the form of ice discs 70-200 mm in diameter was recorded in Shabalinsk and Svechinsk Districts of Kirov Region. Such events are very rare in this area. On 14 July a 150-200 m wide and 700 m long whirlwind was experienced in the village of Krasnoe, Zalegoshensk District, Orlov Region. On 16 July a severe hurricane and dust storm struck the south of Irkutsk Region. In many areas of the Region power was interrupted for several days. On 5-6 July Typhoon Mindulle hit Maritime Territory. It brought heavy rains and hurricane wind (32-34 m/s).

In August air temperature in Russia was near the long-term average. As for precipitation, maximum anomalies were noted in the Northern Caucasus. On 10-12 August showers accompanied by hail and squally wind of up to 23-28 m/s were reported. They led to rain floods on Terek and Upper Kuban, and mudflows in mountain areas of Northern Osetia. On 19-21 August heavy rainfall was reported again throughout the region. The most intensive rainfall was observed in Labinsk District of Krasnodar Territory. It received 83 mm in 1 hour. Heavy rains produced rain floods on Laba and its tributaries. In the second half of August the weather became favorable for a whirlwind at the sea-land boundary. Near Tuapse and Adler whirlwinds were observed several times over the sea, but they did not sweep inland.

On most of the territory of Russia early autumn was marked by insignificant temperature anomalies. Temperature was 2 ^oC above the norm in European Russia, (Northeastern region, Middle Volga and Orenburg Region), Chukotka and Khabarovsk Territory. At the end of the first ten-day period of September the weather in the south of the Far East (Maritime Territory and Sakhalin) was dictated by Typhoon Songda. The east of Maritime Territory received up to 105 mm of precipitation and experienced winds of up to15-20 m/s. In Vladivostok wind gusts were as strong as 28 m/s. In Sakhalin rains brought by Typhoon Songda caused water level rise in rivers. Typhoon was much weaker when it reached Kamchatka, but still it brought heavy rains (40-88 mm) and winds of up to 20-28 m/s.

In October a centre of cold was formed in Yakutia with air temperature 7 ^oC below the norm. Record precipitation was reported from Ural. On 12-13 October the region experienced heavy snowfall accompanied by winds of up to 15-20 m/s and snow storms. A climate frequency of snow occurrence in October is once in 5-6 years. In Chelyabinsk the above snowfall appeared to be the heaviest in the last 30 years, and in Ekaterinburg – in the last 20 years.

November 2004 was very warm on most of the territory of Russia (Fig. 2). A centre of maximum temperature anomalies was formed over Evenki Autonomous Area. The anomalies here exceeded 10 ^oC. The second ten-day period was the warmest. Mean daily air temperature in the centre was more than 20 ^oC higher than the long-term average. On 19 November mean daily air temperature at Tura meteorological station amounted to 2.6 ^oC, i.e. 31.4 ^oC above the norm. On 20 November Oleminsk meteorological station reported the daily air temperature anomaly to be 24.5 ^oC. Deep cyclones traveling across Maritime Territory brought heavy snowfall, snowstorms and winds of up to 25-30 m/s to Sakhalin and Kamchatka. In European Russia Krasnodar Teritory and Adygeia received from 46 to 239 mm of precipitation (300-600% of the monthly norm). Heavy snowfalls caused wet snow loading as thick as 220 mm. It resulted in numerous disruptions of power lines and interruption of power in Labinsk and Mostovsk Districts. Temperature rise and snowmelt triggered snow-rain floods on southeastern and southwestern tributaries of Kuban River. On 18-19 November a deep Atlantic cyclone brought severe weather to Kaliningrad Region. Heavy rains and strong winds of up to 25-30 m/s were reported. Surges led to dangerous water level rise in the Pregol River.

In the first ten-day period of December in Krasnodar Territory and Adegeia persistent rains and temperature rise resulted in snowmelt and made hydrological situation complicated. Floods were reported on Kuban and other rivers. For Asian Russia the end of the years was abnormally cold. On most of the territory air temperature was 4 ^oC below the norm and in the centre of cold temperature anomalies reached -7.1 ^oC (Tura) and -7.4 ^oC(Olekminsk). In Evenkia air temperature below -52 ^oC was reported.