<p>Last year I did an online summer course on remote sensing of volcanoes held by the University of Hawaii at Hilo. During the course, we had a presentation about the monitoring campaign during the <a href="https://en.wikipedia.org/wiki/2018_lower_Puna_eruption" rel="nofollow noreferrer">2018 Kīlauea eruption</a>. This eruption evolved from multiple fizzures that opened and resulted in a lava stream eventually ending into the sea, creating 875 acres (354ha) of new land. While presenting, the professor remarked that the lava flowing into the sea &quot;created all kinds of steam and generated its own weather&quot;.</p>
<p>I went to dig a little deeper and found a <a href="https://rmets.onlinelibrary.wiley.com/doi/pdfdirect/10.1002/wea.3589?casa_token=ySKMrX7l380AAAAA:QMQKc09TTb8LLUDYnfcdeOJVhxSovQkJxBLyY-PaBbtdC03GudqnTAfv3WsLPWF_O5VTpKpD_A8_2j3Q" rel="nofollow noreferrer">detailed account of the weather situation during the eruption by the Royal Meteorological Society</a>, and a story of possible volcanic-induced rain on <a href="https://www.forbes.com/sites/marshallshepherd/2018/07/11/lava-from-the-mt-kilauea-volcano-may-be-creating-its-own-rainfall/?sh=1def2f702956" rel="nofollow noreferrer">Forbes</a>. In this article, NOAA meteorologist James LaDue is quoted saying that:</p>
<blockquote>
<p>Here’s a lesser-known side effect of Kilauea’s latest eruptive tantrum - lava effect rain. Areas around the eruption saw nearly 10” of rain (on the date in question). The resulting rain partially crusted over the lava flows according to the U.S. Geological Survey. These rain cells weren’t any deeper than 15,000 ft deep but their persistence led to amazing totals. A previous lava effect rain event was much deeper, produced hundreds of lightning discharges, and numerous vortices (some possibly tornadoes).</p>
</blockquote>
<p>From what I have read, scientists still seemed to guess about the exact mechanisms behind it. Nevertheless, I was wondering if the contribution of steam resulting from the lava entering the sea would be able to produce such rainfall. Especially now with the current (September 2021) <a href="https://www.euronews.com/2021/09/29/lava-from-la-palma-volcano-reaches-ocean-amid-toxic-gas-fears" rel="nofollow noreferrer">eruption of the Cumbre Vieja</a> at the Canary Island La Palma leading to lava flowing into the sea as well.</p>
<p>So: can steam resulting from lava entering the sea trigger rainfall? Or is volcanic-induced rainfall (if it exists) more influenced by local context, like the climate, latitude, or prevailing wind direction?</p>

CC BY-SA 4.0
2021-09-30T09:02:24.687Z
a volcanic eruption releasing ash will cool the atmosphere and result in less rain as a result of colder air being able to hold less water.lava is not very heat conductive so a lot less heat will be transfered to the water than you might think.
trond hansen
CC BY-SA 4.0
2021-09-30T09:12:51.297Z
My question was more inclined towards the steam that results from the lava flowing into the sea, which might cause rain at some point. The mitigating effect of ash could be an interesting aspect to that
saQuist
CC BY-SA 4.0
2021-09-30T13:45:17.397Z
I've never heard of that, but I'm genuinely interested if you can find a reference to this phenomenon! What is certainly known is that the atmospheric sulfur droplets due to lava/water interactions will turn to acid rain *if it rains*. It happened during the 2018 eruption of Kīlauea and it is now feared at La Palma. But it doesn't mean it will enhance the probability of rain.
Jean-Marie Prival
CC BY-SA 4.0
2021-09-30T13:49:07.907Z
On the other end, there is [a theory](https://doi.org/10.1038/s41586-020-2172-5) that it is rain in the first place that triggered the 2018 Kīlauea eruption. So if the eruption in turn triggered rain, it would come full circle. :)
Jean-Marie Prival
CC BY-SA 4.0
2021-09-30T13:51:35.313Z
I'll be back with an edit as soon as I have dug up the details of the story ; ) But it might be the Kīlauea eruption that I was talking about
saQuist
CC BY-SA 4.0
2021-10-01T06:59:01.380Z
@trondhansen think it's longterm that ash would reduce the moisture content of air globally. Shortterm (on order of days) preventing sunlight shouldn't affect moisture content much locally at least? Does make sense about heat conductivity though. Be interesting to know how much lava increases evap. Reduced sunlight would limit the instability that gives heavy rain to many locations, though local climo varies,  as in [Hawaii](https://scholarspace.manoa.hawaii.edu/bitstream/10125/1852/wrrctr112.PDF)... extra evaporation could = greater rain for situations of forced lift (such as topographic)
JeopardyTempest
CC BY-SA 4.0
2021-10-01T09:37:49.810Z
Added details and sources as much as I could find. I tried to keep it brief, but those who are interested can follow the links.
saQuist
<volcanology><rainfall><volcanic-eruption>
How common are volcanic-induced rain events?
saQuist
# How common are volcanic-induced rain events?

(Asked by: username_0 on 2021-09-30)

Last year I did an online summer course on remote sensing of volcanoes held by the University of Hawaii at Hilo. During the course, we had a presentation about the monitoring campaign during the [2018 Kīlauea eruption](https://en.wikipedia.org/wiki/2018_lower_Puna_eruption). This eruption evolved from multiple fizzures that opened and resulted in a lava stream eventually ending into the sea, creating 875 acres (354ha) of new land. While presenting, the professor remarked that the lava flowing into the sea "created all kinds of steam and generated its own weather".

I went to dig a little deeper and found a [detailed account of the weather situation during the eruption by the Royal Meteorological Society](https://rmets.onlinelibrary.wiley.com/doi/pdfdirect/10.1002/wea.3589?casa_token=ySKMrX7l380AAAAA:QMQKc09TTb8LLUDYnfcdeOJVhxSovQkJxBLyY-PaBbtdC03GudqnTAfv3WsLPWF_O5VTpKpD_A8_2j3Q), and a story of possible volcanic-induced rain on [Forbes](https://www.forbes.com/sites/marshallshepherd/2018/07/11/lava-from-the-mt-kilauea-volcano-may-be-creating-its-own-rainfall/?sh=1def2f702956). In this article, NOAA meteorologist James LaDue is quoted saying that:

> Here’s a lesser-known side effect of Kilauea’s latest eruptive tantrum - lava effect rain. Areas around the eruption saw nearly 10” of rain (on the date in question). The resulting rain partially crusted over the lava flows according to the U.S. Geological Survey. These rain cells weren’t any deeper than 15,000 ft deep but their persistence led to amazing totals. A previous lava effect rain event was much deeper, produced hundreds of lightning discharges, and numerous vortices (some possibly tornadoes).

From what I have read, scientists still seemed to guess about the exact mechanisms behind it. Nevertheless, I was wondering if the contribution of steam resulting from the lava entering the sea would be able to produce such rainfall. Especially now with the current (September 2021) [eruption of the Cumbre Vieja](https://www.euronews.com/2021/09/29/lava-from-la-palma-volcano-reaches-ocean-amid-toxic-gas-fears) at the Canary Island La Palma leading to lava flowing into the sea as well.

So: can steam resulting from lava entering the sea trigger rainfall? Or is volcanic-induced rainfall (if it exists) more influenced by local context, like the climate, latitude, or prevailing wind direction?

**Tags:** volcanology, rainfall, volcanic-eruption

> **Comments:**
> **username_1**: a volcanic eruption releasing ash will cool the atmosphere and result in less rain as a result of colder air being able to hold less water.lava is not very heat conductive so a lot less heat will be transfered to the water than you might think.  
> **username_0**: My question was more inclined towards the steam that results from the lava flowing into the sea, which might cause rain at some point. The mitigating effect of ash could be an interesting aspect to that  
> **username_2**: I've never heard of that, but I'm genuinely interested if you can find a reference to this phenomenon! What is certainly known is that the atmospheric sulfur droplets due to lava/water interactions will turn to acid rain *if it rains*. It happened during the 2018 eruption of Kīlauea and it is now feared at La Palma. But it doesn't mean it will enhance the probability of rain.  
> **username_2**: On the other end, there is [a theory](https://doi.org/10.1038/s41586-020-2172-5) that it is rain in the first place that triggered the 2018 Kīlauea eruption. So if the eruption in turn triggered rain, it would come full circle. :)  
> **username_0**: I'll be back with an edit as soon as I have dug up the details of the story ; ) But it might be the Kīlauea eruption that I was talking about  
> **username_3**: @username_1 think it's longterm that ash would reduce the moisture content of air globally. Shortterm (on order of days) preventing sunlight shouldn't affect moisture content much locally at least? Does make sense about heat conductivity though. Be interesting to know how much lava increases evap. Reduced sunlight would limit the instability that gives heavy rain to many locations, though local climo varies,  as in [Hawaii](https://scholarspace.manoa.hawaii.edu/bitstream/10125/1852/wrrctr112.PDF)... extra evaporation could = greater rain for situations of forced lift (such as topographic)  
> **username_0**: Added details and sources as much as I could find. I tried to keep it brief, but those who are interested can follow the links.  

---

## 0 answers

