US-4814933 Northern Lights in Alaska

Northern Lights (aurora borealis) are caused by a reaction of ionized particles in the atmosphere near the Earth’s poles and are typically visible in northern latitudes from late autumn to early spring.

In Alaska it is even possible to see Northern Lights in  Anchorage but the Lights would be a bit lower on the horizon and light pollution makes it a lot more difficult. 

A great location is Nancy Lake State Recreation Area and locals do say that the views from Flattop Overlook are spectacular.  Another recommended spot is the Glenn Alps. Fairbanks, Nome as well as Denali National Park are also said to be other good locations.

This postcard shows the Northern Lights in Alaska over Portage Lake and Chugach Mountains.  This postcard came from Ruth (22 August 2017).

BR-3969501 The Northern Lights - aurora borealis in Artic Norway

This postcard of the Northern Lights (aurora borealis) in Artic Norway came from Fernando F. (5 July 2016) Postcrossing.
For other Northern Lights postcard, go to "Natural Phenomena" page.

The Aurora Australis or Southern Lights

The Aurora Australis or Southern Lights are mesmerizing, dynamic displays of light that appear in the Antarctic skies in winter.  It is also possible to see the Southern Lights from Tasmania, Australia. These four postcards from Australia Post show the Southern Lights seen from various locations in Tasmania.

Southern Lights from Browns River, Kingston Beach, Tasmania

What is the Aurora Australis?

Aurora is the collective name given to the photons (light) emitted by atoms, molecules and ions that have been excited by energetic charged particles (principally electrons) travelling along magnetic field lines into the Earth’s upper atmosphere. Aurora results from the interaction of the solar wind with the Earth’s magnetic field.

Southern Lights from Goats Bluff, South Arm Peninsula, Tasmania

The amazing colour displays and formations are produced by the solar wind — a stream of electrons and protons coming from the sun — as it collides with gases in the upper atmosphere. These collisions produce electrical discharges which energise atoms of oxygen and nitrogen causing the release of various colours of light. Earth’s magnetic field channels these discharges toward the poles. Variations in sunspot activity or the occurrence of so-called ‘coronal holes’ can often considerably enhance the auroral discharge adding to the intensity and duration of the displays.

Southern Lights from Dru Point, Margate, Tasmania

What are the Colours of the Aurora?

Auroral displays appear in many colours with pale green and pink the most common. However, different shades of red, yellow, green, blue, and violet have all been observed. The brightest auroral colour is generally a green light emitted by excited oxygen atoms. A red diffuse glow results from another oxygen atom transition. A purple colour results from a transition in a Nitrogen molecular ion. The mixture of the major green, red and purple emissions may combine to give aurora a general ‘whitish’ appearance. The colour variations are a product of the altitude of the storm and the density and composition of the ions at that altitude. The folding effect results from the electric field induced on either side of the auroral curtain by the electrons.

Southern Lights from Coles Bay, Tasmania

Source: Antarctic Connections

BY-1534531 A starry night in Belarus

This lovely postcard of a starry night came from Maxim (24 June 2015) Postcrossing.

A tornado in the USA

A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. The most violent tornadoes are capable of tremendous destruction with wind speeds of up to 300 mph. They can destroy large buildings, uproot trees and hurl vehicles hundreds of yards. Damage paths can be in excess of one mile wide to 50 miles long. In an average year, 1,000 tornadoes are reported in the USA alone.

Tornadoes come in many shapes and sizes, but they are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust. Most (less violent) tornadoes have wind speeds less than 110 miles per hour (177 km/h), are about 250 feet (76 m) across and travel a few miles (several kilometres) before dissipating.

Most tornadoes form from thunderstorms. In the USA, when warm, moist air from the Gulf of Mexico meets cool, dry air from Canada, instability is created in the atmosphere. A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.

This very interesting postcard came from Cathy (beesknees) 3 October 2014 DS Postcrossing.

RU-2568307 Northern Lights северное сияние - Russia

Contrary to intuition, seeing the Northern Lights isn't just a matter of heading "north." The Lights usually circle the globe in a circular or elliptical band centered on the earth's North Magnetic Pole, which is not at the same location as the North Geographic Pole, but rather is offset in the direction of northern Canada. The Northern Lights oval, meaning the area with the highest probability, covers most of Alaska, northern parts of Canada, the southern half of Greenland, Iceland and Northern Norway and the northernmost areas of Sweden and Finland, as well as the western half of the Russian north (with the Kola Peninsula of Murmansk Oblast being the most popular viewing spot).

A website www.smartertravel.com recommends the following as the best places to watch the Northern Lights in Russia.

The Kola Peninsula, snaking towards Scandinavia in northwestern Russia, is one of the principal lights-watching areas, thanks to its prime location on the northern lights' belt and a number of guided excursions that run from the Arctic city of Murmansk. Get there in December or January and you'll be gifted with pitch-black days and nights as the sun disappears from view for around six weeks. Alternatively, Severodvinsk is renowned for having some of the brightest lights in Russia, with red and green glows even visible from inside the city. And Salekhard, the world's only city located on the Arctic Circle, is firmly inside the superior viewing zone.

This postcard came from Elena (2 May 2014) Postcrossing and was sent from the far north of Russia (Barents Sea coast) from the small town of Polyarny, Murmansk Oblast on the Western side of the Kola Peninsula.  She said that the Northern Lights shown in this postcard occurred near where she lived.

SW AP-060 CA-816037 Aurora Borealis - Canada

The Northern Lights (Aurora Borealis) can be seen on a clear winter night from many parts of northern Canada.

From an official site of the Canadian Tourism Commission (quite a sales pitch!):

Race to the window or run outside to see ribbons of green, red, blue and purple rippling across the sky, gathering momentum until the Northern Lights shimmer and loop over the entire horizon in surreal swathes of colour. Watch in silence in Nunavut and you’ll understand how many Inuit believe the lights become so intense they sing or crackle. The Aurora Borealis is Mother Nature’s light show so grab a front row seat in fall, winter and early spring when nights are long and dark. Try your luck at fly-fishing for Arctic Char by the lights of the Aurora in far Northern Quebec or pair light-peeping in the Northwest Territories with a locally sourced, gourmet meal of caribou, or pickerel plucked from an icy lake near your log lodge. The Aurora is so bright it can light the way for snowmobilers on Labrador's epic Cain's Quest or for dog mushers and cross-country skiers in the Yukon. But the breathtaking displays are just as enjoyable from within the cozy confines of a cabin, tent or glimpsed through the steam of an outdoor hot tub in the lap of luxury. Then slide under a duvet or into a sleeping bag and dream of Technicolor cosmic fairies.

This beautiful postcard was sent by Sarah K (blubutterfly) of Alberta, Canada (23 April 2014) Swap-bot.
.....
This second postcard is a Zazzle card from Meeghan (Postcrossing, July 2018) who said that they could see the Northern Lights from their home location.

and the stamp that she used also shows (I think) the Northern Lights over Canada.

Aurora over Mt Noulja in Abisko National Park, Sweden

From a Swedish Tourist website:

Swedish Lapland in the far northwest corner of Sweden is a vast area of Arctic plains, forests, mountains, glaciers, lakes and rivers. It is remote, it is wild and it is adored by outdoors enthusiasts and adventure seekers for precisely those two reasons.  Because of Swedish Lapland’s proximity to the magnetic north, Swedish Lapland is a hot spot for the Northern Lights phenomenon.
The Northern Lights appear around the beginning of September to around the end of March all over Swedish Lapland. The very best chance of seeing the Northern Lights is at the Aurora Sky Station in Abisko National Park. There is no guarantee because no one can guarantee a natural phenomenon.

I received this postcard from Henrik Lundgren of Gothenburg, Sweden in February 2014..

The Northern Lights - Aurora Borealis in Finland

The ‘Northern Lights’ is a common name for the Aurora Borealis in the Northern Hemisphere.

On the official Travel Site of Finland website, it is claimed that Finland is one of the best places on Earth to spot the Northern Lights and that they appear on more than 200 nights a year in Finnish Lapland.

This postcard came from a direct swap on Postcrossing with Taru Harkko  of Finland who wrote to say that this postcard does not do justice to the real thing.

This postcard came from Jelena of Croatia (18 May 2016) who sent me this postcard as she knew I like Northern Lights.

What is an aurora?
An aurora is a natural light display in the sky particularly in the high latitude (Arctic and Antarctic) regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere (thermosphere). The charged particles originate in the magnetosphere and solar wind and, on Earth, are directed by the Earth's magnetic field into the atmosphere.

The first postcard came in an envelope which carried this nice stamp of Finland.  It featured the
Pallas-yllästunturi National Park and was issued in 2009.