Black flies in Alaska

Yes — black flies are recorded in Alaska. The GBIF biodiversity database holds 63 verified black fly records from the state — one of the highest counts in the country. Sightings concentrate in July to August. Onset: often painless at first, itch builds over hours. Duration: up to a week, sometimes with lasting swelling.

Black fly bites in Alaska: what the mark looks like

Black flies cut a small hole and pool blood, so the classic finding is a pinpoint blood spot that later swells and itches intensely. They crawl into hair and under collars, which is why bites cluster at the hairline and behind the ears rather than on open skin.

Locally, the species most often confused with it are honey bee sting, bald-faced hornet sting — all of which are also recorded in Alaska.

Black fly season in Alaska specifically

Records in Alaska concentrate in July to August, which is what local sighting data shows rather than a national average — seasonality shifts substantially with latitude. The general bite season in Alaska runs May to September.

Because fast-flowing streams and rivers — larvae need moving water, so they are absent from still ponds, exposure in Alaska tends to be concentrated in specific places rather than spread evenly — which is why a bite history ("where were you in the 24 hours before?") narrows the answer faster than the appearance of the mark.

Month by month in Alaska

These are the 63 Alaska records broken out by the month they were recorded — not a national curve redrawn for the state. Records appear in 5 of the 12 months here. The single busiest month is August with 44 records (75% of the state total).

Counts are observations submitted to GBIF, not bites. They tell you when the animal is out and being noticed in Alaska; they do not tell you how many people were bitten. The thinnest month with any record at all is May (1).

How Alaska compares

Across the 27 states with any black fly records, Alaska ranks 4th with 63. The state directly above it is Wisconsin (99). Directly below is New York (53). The highest count anywhere is Pennsylvania (278).

Inside Alaska itself the picture is different again: of the 9 biting species we track with records here, this one is 3rd and accounts for 6% of the 1,009 records logged in the state. A species can be common nationally and marginal in one state, or the reverse — which is the whole reason this page exists separately from the national guide.

Care

1. wash, cold pack, antihistamine
2. avoid scratching — these bleed and crust easily

Avoiding black flies in Alaska

• fine-mesh head net in black fly season
• cover wrists and ankles
• avoid riverside trails in late spring at peak emergence