Idaho · river
Portneuf River at Topaz
Live conditions for this USGS-monitored stretch of water, updated every 15 minutes.
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Paddle Score, from live wind and water conditions
Wind
7 mph
gusting to 7 mph
Air temp
55°F
0% chance of rain
River flow
73.3 cfs
very low for this date
Best day to paddle this week
Monday · 98
Today
66
83°
Fri
49
80°
Sat
33
85°
Sun
51
67°
Mon
98
69°
Best
Tue
73
77°
Wed
98
76°
Scored from each day's peak forecast wind, heat, and rain chance — river flow isn't forecastable, so check back before you load the boat.
Wind, next 12 hours
mph| Hour | Wind (mph) | Gusts (mph) |
|---|---|---|
| 8a | 8 | 9 |
| 9a | 5 | 5 |
| 10a | 0 | 5 |
| 11a | 5 | 14 |
| 12p | 9 | 13 |
| 1p | 11 | 19 |
| 2p | 14 | 19 |
| 3p | 14 | 22 |
| 4p | 14 | 22 |
| 5p | 15 | 24 |
| 6p | 16 | 20 |
| 7p | 12 | 20 |
Is this flow normal for September 10?
Today's 73.3 cfs is 48% below the median for this date — which counts as very low water here.
The median flow on this date is 141 cfs, across 112 years of USGS record at this gauge. Whether that is runnable depends on the stretch — this is context, not a recommendation.
Why this score
- Wind — 7 mph — calm, ideal for any boat±0
- Cold — 55°F — dress for the water, not the air-8
We don't have launch notes for this one
This page is built from the USGS gauge at this location, so the flow and weather are real — but we haven't verified where to put in, what the hazards are, or whether this stretch is legal or sensible to paddle. We'd rather say that than invent it. The links below are where to find out.
We also don't have a verified safe-flow range here, so the Paddle Score reflects weather only. Judge the flow number against local knowledge, not against our score.
Do your own homework
We show you live conditions. For local knowledge — where to put in, what the hazards are, whether it's worth the drive — here's where paddlers actually talk about this water. We don't vet these sources; check the dates and judge for yourself.
- Paddler discussion on Reddit
Trip reports and local warnings, straight from the source
- Search American Whitewater
Rapid classifications and gauge-linked run descriptions
- Satellite view and access roads
Check parking, put-ins, and what the banks actually look like
- Video from this water
The fastest way to see the character of a run before you drive
- USGS gauge 13073000
Full hydrograph, historical flows, and station metadata