Californie:trop de neige & de canicule..

[sacréfilou]

OK..je sais..c'est en Anglais... /emoticons/tongue@2x.png 2x" width="20" height="20"> .mais c'est la BBC quand même ! /emoticons/wink@2x.png 2x" width="20" height="20">

SULTRY SOUTHWEST STATES SUFFER FROM WINTER SNOW by Rob McElwee

This year saw one of the best skiing seasons for many years across the Colorado and Sierra Nevada slopes. Droves of tourists flocked to the area, but now its pay-back time, thanks to the jet streams

Jet streams control the general track of low pressure systems, which usually bring unsettled conditions. This year, the jet stream over the states was further south than usual. The low pressures passed through southern states before then heading in a northeast direction, towards New York and Boston. Having the low pressure so far south in the winter, and crossing the Sierra Nevada and Colorado mountains meant significant snowfalls for these areas. In some places the snow depth amounted to an astonishing 5 metres, which keen skiers revelled in. This has allowed vast amounts of snow to be stored (snow-pack) on the mountain tops, which is now beginning to melt, fast.

The problem now, is the southeast states are now experiencing some very high temperatures, in the region of the mid 30's, in terms of degrees celsius. This is allowing the snow to melt extremely quickly, and with snow-pack some 190%, that’s almost double the normal, so were talking of a lot of water entering the rivers at once. Already the Sacramento River is reaching flood levels and the Merced, which courses through the Yosemite National Park has already overflowed. With warmer temperatures and lots more snow still to melt, swelling rivers and rain forecast for the weekend, homeowners are becoming worried about the rising river levels. All this water was expected and the authorities have made sure that there is still plenty of room in the dams, to hopefully control the extra flow.

There are some benefits from this extra liquid, as the Californians have suffered from droughts in recent years, and a real deficit in ground water levels over the last six years. This is good news for the farmers who need to irrigate their fields in the long hot summers experienced in this area and again for the tourist industry as it should make for good conditions in the rivers for rafting.

Norway is facing a similar problem with very warm weather expected next week and heavy snow-packs waiting in the mountains. The last time Norway had major flooding in this way was 10 years ago, in 1995.

[sacréfilou]

Reuh..... /emoticons/tongue@2x.png 2x" width="20" height="20">

A ce propos, ci-joint ( en Anglais of course /emoticons/wink@2x.png 2x" width="20" height="20"> ) copie d'un mail qui m'a été envoyé de Grass Valley, localité située à 740 m d'altitude, dans le nord de la Californie..

"Rain, rain and more rain! May is turning out to be a very wet month. Several places in the north state have already set records as the wettest May ever (although not here). We are, however, at 298% of average for the month of May! The jet stream took aim on Northern and Central California this past week giving up copious amounts of rain. The result of all this rain is booth good and bad. On the good side, fire danger is non-existent, everything is well watered and allergies are just about gone. On the bad side, the cherry crop in Northern and Central California is just about wiped out, the grape crop in the Napa Valley is suffering from blossom rot and numerous areas are experiencing flooding. Reservoirs are near 100% capacity and we’ve only seen 2% of the entire snowmelt. Thusly, rivers throughout the North State are running very high, very swift and are very cold.

Now a hot high-pressure system is pushing up from the southeast. Valley locations are expecting temperatures in the 90’s(F) (I believe that would be the low to mid 30’s in C) this week while we in the foothills should see 80’s(I believe that would be the upper 20’s to lower 30’s in C). Nevertheless, we shouldn’t think all the rain is done with for the summer; it looks like more rain is headed our way for the upcoming holiday weekend. If it ever gets dry enough, I’m putting my garden in!

May tomorrow be a good day for you, weather or not,

Dan"

[GD]

pluie en grande quantité plus fonte rapide de la neige en énomr quantité encore à cette époque (il parle de plus de 5 m par endroit..) vont donner de grosses inondations!

Ceci est du au cumul anormal de pluies plutôt qu'à la neige non?

[Invité Guest]

Et que veut dire cet article??? Car moi et l'Anglais ça fait 31 688

[jack_lb88]

voilà ce que j'ai compris pour les non anglophones (je résume les deux messages en anglais) :

Cette année aux états-unis, le courant-jet est passé plus au sud que d'habitude entrainant de fortes chutes de neige sur le colorado et la sierra nevada (190% par rapport à la moyenne, 5 mètres par endroit).

Le problème actuel est que ces régions subissent des températures d'environ 35°C + dans le nord de la californie des chutes de pluie abondantes (298% par rapport à la normale pour le mois de mai à grass valley).

voilà les clés de l'équation : grosses pluies sur beaucoup de neige = inondations.

La sacramento river a atteint son seuil critique et la merced river dans le parc national du yosemite a déjà débordée.

en esperant avoir été utile à quelques uns.