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Fire danger

PostPosted: May 29th, 2017, 5:03 pm
by Frisk
Probably time for some rain, especially up north.

Re: Fire danger

PostPosted: Jun 16th, 2017, 9:11 pm
by Glacier
Extreme fire danger out there. Alexis Creek, Nemiah, Puntzi Mountain, Tatla Lake. All extreme. Plus one spot in our fire zone (Ashcroft).

drJune162017.png

Re: Fire danger

PostPosted: Jun 17th, 2017, 1:13 am
by What_the
Graphs. Right up glaciers alley...
And the first to post lol

Sorry, carry on.

Re: Fire danger

PostPosted: Jun 23rd, 2017, 1:23 pm
by Symbonite
well its that time of the year again....before its too late...ban campfires!

Re: Fire danger

PostPosted: Jun 23rd, 2017, 1:55 pm
by Glacier
What_the wrote:Graphs. Right up glaciers alley...
And the first to post lol

Sorry, carry on.

I was last as well until you showed up. Thanks for ruining everything!

dr-June23-2017.png

Re: Fire danger

PostPosted: Jun 26th, 2017, 2:12 pm
by Glacier
It's highly likely that the lightning will make its way down our way this week. We will likely get some rain too, but not a lot.

firedangerrating.jpg

Re: Fire danger

PostPosted: Jun 26th, 2017, 5:11 pm
by Frisk
Check out some of the weather conditions in BC right now & then compare those locations with the fire danger map glacier posted above.

Kamloops
Temperature: 32.0°C
Humidity: 12%
Wind: SW 38 gust 61 km/h

Clinton
Temperature: 26.0°C
Humidity: 7%
Wind: WNW 30 gust 48 km/h

Lytton
Temperature: 31.3°C
Humidity: 14%
Wind: S 37 gust 55 km/h

Re: Fire danger

PostPosted: Jun 26th, 2017, 5:21 pm
by seewood
Those humidity readings are low, really low. Fire behavior at those low RH values can create explosive fire behavior, especially with some wind.

Re: Fire danger

PostPosted: Jun 27th, 2017, 8:10 am
by bob vernon
Say...... just what is "tinder"? And why is it so dry?

Re: Fire danger

PostPosted: Jun 27th, 2017, 8:27 am
by Fancy
Google is your friend:
Tinder is easily combustible material used to start a fire.
Wikipedia

Re: Fire danger

PostPosted: Jun 27th, 2017, 12:21 pm
by Frisk
The fire danger rating way up in the hills at the Brenda mines weather station (extreme rating) yesterday was actually higher than the ratings in the valley bottom at the West kelowna, fintry and penticton stations (high rating).

http://bcfireinfo.for.gov.bc.ca/hprScripts/DgrCls/index.asp?Region=5

Re: Fire danger

PostPosted: Jun 29th, 2017, 11:50 am
by Symbonite
Who cares about campers belly aching about campfires...ban it before someone starts a forest fire....totally preventable fire if there is not fire to begin with.

Re: Fire danger

PostPosted: Jun 29th, 2017, 11:55 am
by gman313
Symbonite wrote:Who cares about campers belly aching about campfires...ban it before someone starts a forest fire....totally preventable fire if there is not fire to begin with.


banning smoking would actually save more forest fires. More start from cigarettes than campfires

Re: Fire danger

PostPosted: Jun 29th, 2017, 1:10 pm
by Glacier
Frisk wrote:Check out some of the weather conditions in BC right now & then compare those locations with the fire danger map glacier posted above.

Kamloops
Temperature: 32.0°C
Humidity: 12%
Wind: SW 38 gust 61 km/h

Clinton
Temperature: 26.0°C
Humidity: 7%
Wind: WNW 30 gust 48 km/h

Lytton
Temperature: 31.3°C
Humidity: 14%
Wind: S 37 gust 55 km/h


This is very interesting. 7% in Clinton!!! The Clinton weather station is up on the Cariboo plateau. We are talking over just under 4,000ft elevation, and relative humidity tends to increase with elevation.

I tried to check out Ashcroft, and I get an error. It seems that it was so dry the instruments crapped out! We can see at 8pm when the dewpoint temperature was -6C. If the dewpoint were like that an hour earlier, the relative humidity would have been damn close to zero.

From Wikipedia:

This can be expressed as a simple rule of thumb:

For every 1°C difference in the dew point and dry bulb temperatures, the relative humidity decreases by 5%, starting with RH = 100% when the dew point equals the dry bulb temperature.

The air was so dry, it's off the charts, as in the rule of thumb doesn't work. I would guess it was well under 5%.

Anyway, back to Clinton. Clinton is at close to 4,000 feet and Ashcroft is at about 1,000 ft, so the air is much drier in Ashcroft (relative humidity). We can compare the two in the links in this post from the 26th. Now, the Clinton airport is a relatively new station, but the old station (also on the plateau, but lower), crapped out just like Ashcroft.

So, it seems these weather stations cannot record relative humidities under 10%, but the new Clinton airport station can.

Now, let's look at the data from the airport. Between 1pm and 7pm, the dew point temperature tanked (the lower the dewpoint, the less moisture in the air). RELATIVE humidity is basically a measure of the difference between the actual temperature and the dewpoint. The bigger the difference, the lower the relative humidity. That's why it can be 100% in the morning and 30% in the afternoon even though the amount of moisture in the air hasn't changed.

So, the reasonable assumption is that Ashcroft was almost zero. Maybe 4 or 5%. If we look at Clinton, it was 17% at noon, and 20% at 8pm. Between those times, it was down to 7%. Ashcroft was 11% at noon and 8pm, so it was quite reasonably 5% between those times. Crazy!

Re: Fire danger

PostPosted: Jun 29th, 2017, 5:13 pm
by Frisk