Some Atacama rainfall numbers

[RWood]

[The following is extracted from summaries on the Meteochile website - there are almost certainly older observations somewhere, and there are a few missing years for some sites in the ranges I found. I don't have any information about the reliability of the equipment or observations].

These are for the cities Arica, Iquique, Calama and Antofagasta. Calama is in an upland region at 2270m ASL; the other towns are coastal.

Mean annual rainfalls: Arica 1.3mm (1919-2018, 91 years' data), max 17.7mm, 42 zero years
Iquique 1.4mm (1919-2018, 98 years), max 20.0mm, 61 zero years
Calama 6.0mm (1965-2018, 47 years), max 42.4mm, 11 zero years
Antofagasta 4.2mm (1919-2018, 98 years), max 56.4mm, 28 zero years.

The most noteworthy "dry patches" were 0.0 at Antofagasta (1943-1955), 0.1 at Arica (1945-1957) and 0.0 at Iquique (1946-1956).

Atofagasta and Calama, and to a much lesser extent the other 2, have occasionally had significant falls from vigorous cold fronts penetrating further north than usual. In March 2015 25mm fell at Antofagasta in less than 24 hours, causing some flash flooding and mudslides.

(TBC)

[RWood]

The coastal cities get most of their meagre rainfall (in terms of event frequency) from periods of drizzle. Winter cloudiness on the coast increases toward the north, but the annual sunshine totals are not low: cited means are 2400 hrs at Arica, 2870 at Iquique and 3080 at Antofagasta.

In a different league again is the oasis hamlet of Quillagua in Antofagasta province, where only about 8mm has fallen in the last 50 years or so (4mm of that in the autumn 2015 event). The town was relying on the river Loa
for its water supply, but has fallen on troubled times, if the circumstances described in this story still hold:

https://www.nytimes.com/2009/03/15/worl ... chile.html

There are claims that parts of the Atacama have not seen rain in living memory or even for hundreds or thousands of years, but I am unaware of any measurement site that looks as if it could be a candidate by having gone dry for years or decades …

Latest provisional readings for 2018: Arica 0.0, Iquique 0.0 (none since 2015), Calama 3.0mm, Antofagasta 2.6mm.

[Chris W]

The Altiplano is famed for being devoid of rain and microbial life. Yes, I learned that first on Top Gear, but it seems to be true. I don’t know any rainfall stats from the top of my head.

[RWood]

The Altiplano is famed for being devoid of rain and microbial life. Yes, I learned that first on Top Gear, but it seems to be true. I don’t know any rainfall stats from the top of my head.

Don't believe Top Gear. La Paz Aero on the Altiplano gets 600 mm/year, with most of the rain in summer as on the wet lowland sides of Peru and Bolivia. Even on the Chilean Atacama side the rainfall is higher at 3000m+ than on the lowlands. Parts of the Altiplano are very barren though.

[Chris W]

It’s possible they were referring to part of it. It is not the only source I have heard that from.

The Atacama in general I already knew about from my studies, being hyper arid.

[David]

I find it quite remarkable that cities right on the coast beside a huge moisture source (the sea) get practically zero rainfall. I would certainly find that a most boring climate myself!

[RWood]

I find it quite remarkable that cities right on the coast beside a huge moisture source (the sea) get practically zero rainfall. I would certainly find that a most boring climate myself!

I think I could stand it for a while, though the very sunny hinterland would be preferred. I have seen enough rainfall to last me several lifetimes!

[Richard]

I find it quite remarkable that cities right on the coast beside a huge moisture source (the sea) get practically zero rainfall. I would certainly find that a most boring climate myself!

Very little moisture is evaporated off the cold Peru Current seawater, to make a boring climate even more boring the onshore winds must be quite cool yet sub tropical in latitude. There wouldn't be a lot conversations about the weather in those parts, can just imagine kids wide eyed mouths open sitting around listening to Grandad recall the time long ago that it once drizzled ( wow...water falling from the sky) either that or they just think Grandad is full of ****

[RWood]

Antofagasta in particular has a small daily temperature range, just mild and pleasant with lots of sun. Things are very occasionally more exciting at Calama with showers coming off the Andes. Solar radiation at Calama is very high and we noticed it even in mid-April. When Iquique had a rare shower of just a few mm a few years back a couple of house roofs in a poor district fell in ...

[longaotian]

As someone who wants to live in a climate with 3000+ sunshine hours, i think i would have to draw the line . Not only could i not stand having no rain, but it also creates a really ugly looking landscape . I would take Santiago's climate over those anyday.

[RWood]

As someone who wants to live in a climate with 3000+ sunshine hours, i think i would have to draw the line . Not only could i not stand having no rain, but it also creates a really ugly looking landscape . I would take Santiago's climate over those anyday.

My taste is somewhat different - I like the stark beauty - a refreshing change from perpetual greenness. The landscapes around San Pedro de Atacama attract a lot of visitors, with the Andes in view, a salt lake nearby and the "Valley of the Moon". If I hadn't spent my life in relatively rainy and cloudy climates I might have felt differently. But I want a lot of sunshine on any holiday and have done pretty well on overseas trips on that score.

[longaotian]

As someone who wants to live in a climate with 3000+ sunshine hours, i think i would have to draw the line . Not only could i not stand having no rain, but it also creates a really ugly looking landscape . I would take Santiago's climate over those anyday.

My taste is somewhat different - I like the stark beauty - a refreshing change from perpetual greenness. The landscapes around San Pedro de Atacama attract a lot of visitors, with the Andes in view, a salt lake nearby and the "Valley of the Moon". If I hadn't spent my life in relatively rainy and cloudy climates I might have felt differently. But I want a lot of sunshine on any holiday and have done pretty well on overseas trips on that score.

Yep, i like drier landscapes than say the North Island but i still would rather have some sort of vegetation unlike the Atacama desert - what do you think of my ideal climate box i made yesterday?

[RWood]

My taste is somewhat different - I like the stark beauty - a refreshing change from perpetual greenness. The landscapes around San Pedro de Atacama attract a lot of visitors, with the Andes in view, a salt lake nearby and the "Valley of the Moon". If I hadn't spent my life in relatively rainy and cloudy climates I might have felt differently. But I want a lot of sunshine on any holiday and have done pretty well on overseas trips on that score.

Yep, i like drier landscapes than say the North Island but i still would rather have some sort of vegetation unlike the Atacama desert - what do you think of my ideal climate box i made yesterday?

Would prefer less rainfall in the wet part, sun excellent, slightly cooler temperatures preferred.

[Simon Culling]

The dry weather ended with a bang this week with plenty of rain and a waterfall appears to have come back to life after being dry for 10 years. See the BBC video below:

https://www.bbc.co.uk/news/av/world-471 ... hern-chile

I appreciate the rain may not have fallen in the desert, but an interesting story nontheless.

[RWood]

Yes a high altitude event but still helpful. Calama has had a couple of showers this year but the coast is unaffected. Above 3000m or so the erratic summer rainfall is occasionally generous. Various populations rely on the Andean rivers for supply.

[Simon Culling]

Here is a rough rainfall map for the 7 days up to 8th Feb covering most of South America:

https://twitter.com/SteveBowenWx/status ... 6739284993

There appears to have been quite a lot of damage in northern Chile.

[RWood]

Here is a rough rainfall map for the 7 days up to 8th Feb covering most of South America:

https://twitter.com/SteveBowenWx/status ... 6739284993

There appears to have been quite a lot of damage in northern Chile.

Unfortunately they are not set up for uncommon events. Steep gradients make flash flooding pretty serious. But even at a low level the poor can't prepare too well. There was an incident in Iquique once when a few mm of rain collapsed a number of roofs.

[RWood]

Here is a rough rainfall map for the 7 days up to 8th Feb covering most of South America:

https://twitter.com/SteveBowenWx/status ... 6739284993

There appears to have been quite a lot of damage in northern Chile.

The Meteo Chile summary I looked at earlier must have been running a bit late in its YTD updates. On a closer look I found precipitation diaries - on 7-8 Feb Arica had 1.4mm and 4.2mm respectively, and the YTD 5.8mm is already higher than the annual totals for 2014-2018, though the record high of 17.7 mm in 1959 may be a long way off. Calama had 12mm on the 7th and 4 consecutive days of precipitation, very unusual. The YTD value of 18mm is already higher than any annual total since the exceptional 42.4mm in 1992.