Walking the Past: Twin Tunnels and the Old Penstock Route (DH-2/3)

Walking the Past: Twin Tunnels and the Old Penstock Route (DH-2/3)

Trip Name Walking the Past: Twin Tunnels and the Old Penstock Route (DH-2/3)
Trip Start Date Friday, January 23, 2026
Type of Trip Day Hike
Rating DH-2/3
Leader Name Victoria Purkey
Leader Email vicop_1776@hotmail.com
Roundtrip Drive Mileage 296
Carpooling Cost $35
Additional Fees Parking Pass $10-$12 OR Oregon State Parks annual pass
Trailhead Name Mark O. Hatfield West
Longitude/Latitude 45.7035356, -121.4873508
Trip Description Twin Tunnels Route

The round-trip route from the Mark O. Hatfield West Trailhead to the Mosier Twin Tunnels is approximately 7 miles, mostly flat with a firm, paved surface that makes it suitable for a wide range of fitness levels and family-friendly for those comfortable with the distance. This stretch of the Historic Columbia River Highway State Trail offers rolling forested hills, excellent viewpoints of the Columbia River, and a memorable walk through the restored Twin Tunnels—once sealed when I-84 opened and now reopened to foot traffic. It is a scenic, easy-to-moderate winter hike with historic features and sweeping Gorge views. Bring microspikes appropriate for paved surfaces in case of icy conditions.

Penstock Flume Extension

The Penstock Flume is a short, easy-to-moderate add-on hike. The route follows the old penstock catwalk near the former powerhouse, offering unique views of the river, concrete supports scattered by past floods, and an up-close look at early hydroelectric structures. Though mostly flat and on firm surfaces, the flume includes narrow sections, drop-offs, and uneven footing, making it exciting while still accessible for many hikers and families with good supervision. Bring microspikes if conditions are icy, as the surfaces can be slick.

What to Bring
• The 10 essentials
• Warm layers, hat, and gloves
• Traction spikes for ice on paved surfaces

Bring $35 for your driver.

The parking may also be covered by an Oregon State Parks annual pass.
Approximate Mileage 7 miles and 6 (optional)
Elevation Gain 800 feet elevation gain
Departure Time 7:00 AM
Sign up by January 20, 2026

Each participant is responsible for their own safety and being prepared. PLANNING and preparation start with the 10 ESSENTIALS and staying up-to-date on road and trail conditions, permit requirements, party size limits, snowpack, wildfires, and weather.  Visit the ACTIVITY CLASSIFICATION PAGE  for detailed information on difficulty rating for I-MAC trip so you can sign up for activities that best match your fitness and comfort levels.

Visit TRIP COSTS & PASSES for detailed information about trip costs.

To help protect and care for these special places that we enjoy exploring, I-MAC members always practice LEAVE NO TRACE and follow the 7 PRINCIPLES OF LEAVE NO TRACE. Ask your trip leader if you have questions about Leave No Trace or suggestions for helping to reduce our footprint.

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Walking the Past: Twin Tunnels and the Old Penstock Route (DH-2/3)
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Date

Jan 23 2026

Time

All Day

Location

Twin Tunnels and the Old Penstock Route

Category

Organizer

Victoria Purkey
Email
vicop_1776@hotmail.com
REGISTER
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mountaineering practice

I-MAC Basic Mountaineering Course

For those looking to enhance their outdoor adventures beyond backpacking, the mountaineering course is full of instructional knowledge and practical learning to prepare students for summiting mountains in the Pacific Northwest.  The course covers basic and technical climbing skills, including rope handling, anchors and knots, rappelling and ascending, snow and glacier travel, gear selection, and navigation.  Essential safety information is relayed as well, including how to conduct risk assessments, interpret weather conditions, and plan a trip with other climbers.  In addition, the following skills are covered: basic first aid, self-arrest, crevasse rescue, and avalanche awareness.
 
The course is held every year in the spring and includes both classroom sessions and hands-on learning.  Upon course completion, students are given the opportunity to summit PNW mountains on a team-coordinated climb.  The course itself is FREE apart from a nominal gear rental fee and an I-MAC membership.  Additional costs for individual gear may be applicable.  For more information contact Eddie Goss at imac.climbing@gmail.com.
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Community Programs

I-MAC enjoys providing the community with opportunities to come together with other outdoor enthusiasts to learn and share. The Reel Rock Film Fest is one such event. This annual event showcases a set of spectacular films about rock climbing (Think Free Solo, only shorter). REI and local climbing clubs toss prizes into the crowd during the intermissions. Proceeds from the event go to worthy organizations selected by the I-MAC Board.

We also host guest speakers from outside the area to provide presentations on mountain climbs, ski tours, hiking and other backcountry adventures. I-MAC members also provide presentations on a variety of topics from epic club hikes to conservation.

Backpacking School 2023

Backpacking School

Are you interested in learning how to backpack? If yes, then the I-MAC Backpacking School is for you. This free two-day class is offered nearly every year. A combination of indoor and outdoor classes teaches you what you need to know to start backpacking on your own.

The purpose of the backpacking school is to prepare participants for comfortable and safe multi-day backpacking trips. No prior experience in the outdoors is required. Each topic is taught by an I-MAC member with years of experience.

Topics include:
· The ten essentials
· Training for a backpacking trip
· Gear (e.g., tents, sleep systems, water filters, stoves, backpacks)
· Nutrition and cooking
· Water purification
· Route planning
· Navigation including map & compass and digital navigation

The first day consists of lecture-style presentations. The second day includes outdoor field demonstrations of equipment and techniques at a local park. The school culminates in overnight backpacking trips led by I-MAC trip leaders.

Before the course, we recommend you get the book The Backpacker’s Field Manual, by Rick Curtis, and read as much as you can (it is not available through REI). We also recommend that you join I-MAC before the school. Membership will get you access to more information about our trips, both before and after, and about our community.

The school is free and open to the public.

Registration is required.

For inquires, please email to backpacking@imacnw.org.

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Youth Outreach

I-MAC partners with local community organizations to teach youth outdoor skills and provide outdoor experiences, such as hiking. I-MAC has partnered with Boys and Girls Club of Benton and Franklin Countries as well as Girls Scouts of Eastern Washington & Northern Idaho.

Friends of Badger Mtn trail work 2023

Volunteer Trail Work

I-MAC focuses most of their trail work volunteer time on local trails, specifically Badger and Candy Mountains. These trails are used by 300,000 people every year. The trail work is led by I-MAC’s Jim Langdon, who is the FRIENDS OF BADGER MOUNTAIN TRAILMASTER.

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Wilderness First Aid

I-MAC hosts Wilderness First Aid classes, provided by outside agencies, on a semi-regular basis. The most recent class was presented by Longleaf Wilderness Medicine and was held at Columbia Basin College, using both indoor and outdoor spaces. Instruction includes both lecture and hands-on practice. Classes are open to the public and I-MAC members can register before the public.

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Trip Costs & Passes

Trip participants are expected to pay drivers a fee to help cover the cost of fuel and vehicle usage. The per milage rate is occasionally adjusted to reflect the general cost of fuel. We want drivers to feel comfortable that their costs are covered, but we would also never want the cost of carpooling to prevent someone from going on a trip. We aim to keep the rate at an acceptable compromise for everyone.

The current mileage rate of $0.12 per mile was voted on by the I-MAC board in April 2023.

On the first day of the trip, be prepared to pay your driver in cash for the amount noted in the trip cost section of the trip description. Checks are not accepted. Some drivers may accept Venmo or other cash apps. Check with the driver prior to the trip if you would like to pay with a cash app.

PASSES FOR PUBLIC LANDS

We are fortunate to have easy access to city, county, state, and federal public lands. Some of these parks and forest are free while other charge fees. Depending on who manages the land, the required fee or pass is different. Below is information about the three primary passes you’ll need to enjoy federal and state public lands in the Pacific Northwest.

Annual Washington State Parks Discover Pass

Discover Pass is a permit that gives you access to state parks and recreation lands in Washington.

Annual Northwest Forest Pass

The Annual Northwest Forest Pass is honored at all US Forest Service operated recreation sites in Washington and Oregon where a day use fee is required.

America the Beautiful Federal Recreation Lands Passes

There are several different America the Beautiful passes to choose from depending on certain criteria. All the passes cover entrance fees at national parks and national wildlife refuges as well as standard amenity fees (day use fees) at national forests and grasslands, and at lands managed by the Bureau of Land Management, Bureau of Reclamation and US Army Corps of Engineers.

Locally, many of these passes can be purchased at REI. All of the America the Beautiful passes are available at the McNary National Wildlife Refuge office at 64 Maple Street in Burbank. All above-listed passes are also available for purchase online.

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Activity Classification

I-MAC strives to provide experiences for folks of all skill levels. We classify excursions by skill level or experience needed so you can sign up for activities that best match your fitness and comfort levels. This helps ensure the safe and enjoyable experience for the entire group. Before signing up for a trip, read the trip description thoroughly. If you have any questions, contact the trip leader. Our trip leaders are happy to discuss any concerns you may have. Note that these classifications are guidelines only. All trip leaders reserve the right to independently vet trip participants.
 

Hiking: DH = DAY HIKE BP = BACKPACK

1 – Easy

Less than 6 miles and less than 1,000-ft elevation gain per day

2 – Moderate

6 to 10 miles or 1,000 to 2,000-ft elevation gain per day.

3 – Strenuous

10 to 12 miles or 2,000 to 3,000-ft elevation gain per day

4 – Very Strenuous

More than 12 miles or more than 3,000-ft elevation per day.

CLIMBING: G = GLACIER R = ROCK S = SNOW I = ICE

0 – Class

No experience needed. This is a training class.

1 – Easy

Minimum experience needed, ample opportunity for instruction.

2 – Moderate

Moderate experience needed, still a good opportunity for instruction.

3 – Strenuous

Advanced levels of experience needed, little opportunity for instruction.

4 – Very Strenuous

Must be entirely self-sufficient, no instruction provided.

WINTER ACTIVITY: SS = SNOWSHOEING

0 – Class

No skills needed. This is a training class.

1 – Easy

Less than 5 miles and less than 500 ft elevation gain.

2 – Moderate

5 to 8 miles or 500 ft to 1,500 ft elevation gain.

3 – Strenuous

More than 8 miles or more than 1,500 ft elevation gain.

4 – Very Strenuous

Usually requires great effort, could include overnight outings requiring full packs.

WINTER ACTIVITY: XC = CROSS COUNTRY SKIING

0 – Class

No skills needed. This is a training class.

1 – Easy

Less than 6 miles and less than 500 ft elevation gain. Minimal stopping and turning skills necessary.

2 – Moderate

6 to 11 miles or 500 feet to 1,500 ft elevation gain. Stopping and turning skills are important.

3 – Strenuous

More than 11 miles, or greater than 1,500 ft elevation gain. Stopping and turning skills a must.

4 – Very Strenuous

Usually requires great effort and advanced skills. This could include overnight outings requiring full packs.

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Ten Essentials

The 10 Essentials are a collection of first aid and emergency items that can help you in the event of minor injuries, sudden weather changes, or unexpected delays. The 10 Essentials are only the basic items you should have with you. You may need additional items depending on the activity in which you participate (e.g., ice ax, climbing rope, personal locator beacon).
 
THE TEN ESSENTIALS*
The 10 Essentials are organized into ten categories, or systems:
 
NAVIGATION
Map, compass, and GPS system Navigation systems are used when planning your route before your trip, and when you need help orienting yourself in your surroundings during your activity. Know how to use a topographical or relief map as well as your compass or GPS unit before going out.
 
SUN PROTECTION
Sunglasses, sunscreen, and hat Sun protection is necessary to protect your skin and eyes against harsh UV rays that are responsible for sunburns and skin cancer. Consider using sunglasses, sunscreen, and hats. Sun-protection clothing such as pants and long sleeve shirts can also help minimize your exposure to the sun.
 
INSULATION
Jacket, hat, gloves, rain shell, and thermal underwear Nature is unpredictable. Be prepared for sudden changes in weather conditions. Pack an extra layer of clothing that reflects the most extreme conditions you could encounter.
 
ILLUMINATION
Flashlight, lanterns, and headlamp Lighting is indispensable in the outdoors where no conventional light sources can be found. Items include flashlights, lanterns, and headlamps. Headlamps are the preferred light source because they are hands-free. Be sure to pack extra batteries.
 
FIRST-AID SUPPLIES
First Aid Kit Be prepared for emergencies by packing first-aid supplies with you. Start with a pre-made kit and modify it to fit your trip and your medical needs. Check the expiration date on all items and replace them as needed. Consider including an emergency guide in case you are faced with an unfamiliar medical emergency.
 
FIRE
Matches, lighter and fire starters Fire can be an emergency signal and a heat source for cooking and staying warm. Pack matches (preferably waterproof) and fire starters – items that catch fire quickly and sustain a flame (e.g., lighter). Familiarize yourself with the fire use regulations of your park before heading out.
 
REPAIR KIT AND TOOLS
Duct tape, knife, screwdriver, and scissors Carry a basic repair kit with you to help repair equipment. The kit should include items such as duct tape, a knife, and scissors. Consider packing a multi-tool, a compact version of many tools that can include a knife, screwdriver, can opener, etc. Be sure to bring any tools specific to your trip and your activity.
 
NUTRITION
Food You should always be prepared for the possibility of changes to your trip plans. Pack an extra day’s supply of food, preferably no-cook items that have good nutritional value in order to keep your energy high. Salty and easy to digest snacks (e.g., trail mix, nuts, and granola bars) work well for outdoor activities.
 
HYDRATION
Water and water treatment supplies Staying hydrated on your trip is of utmost importance! Physical activity increases your risk of dehydration (loss of water and salts from the body), which can lead to negative health consequences. If you’re active outdoors (hiking, biking, running, swimming, etc.), especially in hot weather, you should drink water often and before you feel thirsty. Prepare your water before you need it and do not allow yourself to become dehydrated. Before heading out on your trip, be sure to identify if there are any bodies of water at your destination that you could collect water from and treat using your water treatment supplies. Learn more about purifying water.
 
EMERGENCY SHELTER
Tent, space blanket, tarp, and bivy Shelter is one of the most important elements during an emergency survival situation. It can protect you from severe weather conditions and exposure to the elements. A tent, tarp, bivy sack, or emergency space blanket are all light weight options for emergency shelter.
 
The I-MAC snowshoe crew starting off strong

Snowshoeing

Snowshoeing is like hiking but done in the winter. You can follow established trails or make your own trails through the snow. Snowshoeing is a great way to get outside during the winter months and explore new areas or see your favorite summer hiking trails in a different season. Snowshoeing is an excellent low-impact aerobic exercise and fun way to stay in shape during the winter months.
 
Few outdoor activities are as beginner friendly as snowshoeing. Snowshoes and poles are affordably priced and can be used for many years. I-MAC also rents snowshoes and poles. I-MAC members lead snowshoe trips December through March depending on the snow conditions.
 

Check out the I-MAC ACTIVITY CALENDAR for upcoming trips. If you are interested in joining an I-MAC adventure, review the ACTIVITY CLASSIFICATION and TRIP COSTS & PASSES  pages before you sign up to ensure the trip is right for you.

Each participant is responsible for their own safety and being prepared. Planning and preparation start with the 10 ESSENTIALS  and staying up-to-date on road and trail conditions, permit requirements, party size limits, snowpack, wildfires, and weather.

 
Outdoor Rock Practice at Wallula Gap

Rock & Ice Climbing

Rock climbing is the sport of climbing up, down, or across natural rock formations or indoor climbing walls often with the aid of ropes and special equipment. Ice climbing is a similar concept except it involves ascending routes that consist only of frozen water and requires some different equipment such as ice screws, crampons, and ice tools. Both sports are physically demanding, can be dangerous, and require technical skills and specialized equipment.
 
For adventure seekers interested in building their skills, I-MAC members lead skill development trips throughout the year as well as trips that require advance skills and knowledge of either sport. I-MAC also rents equipment such as helmets, ropes, and ice axes.
 
Check out the I-MAC ACTIVITY CALENDAR for upcoming trips. If you are interested in joining an I-MAC adventure, review the ACTIVITY CLASSIFICATION and TRIP COSTS & PASSES  pages before you sign up to ensure the trip is right for you.
 

Each participant is responsible for their own safety and being prepared. Planning and preparation start with the 10 ESSENTIALS  and staying up-to-date on road and trail conditions, permit requirements, party size limits, snowpack, wildfires, and weather.

 
Pausing at the pass to take a selfie

Backpacking

Are you looking to extend your outdoor adventure beyond day hikes? Backpacking is similar to hiking except that you bring all your gear with you including food, clothing, sleeping pad and bag, tent, and other personal items. Backpacking requires physical conditioning to ensure you have the stamina to carry the extra weight and be on the move for multiple days in a row. It is also important to have knowledge of map reading, Leave No Trace Principles, and and basic outdoor skills.

I-MAC members lead backpacking trips from easy overnight trips to challenging multi-day adventures even in the winter! Backpacking is a wonderful way to explore hard to reach locations and get off grid for a while.

I-IMAC offers a backpacking school once a year, which is a combination of indoor and outdoor classes designed to teach you what you need to know to get started on your own backpacking adventure. About once a year, I-MAC sponsors a Wilderness First Aid Class for members. The information learned in these classes can help save a life when out in the backcountry.

Check out the I-MAC activity calendar for upcoming trips. If you are interested in joining an I-MAC adventure, review the Activity Classification and Trip Costs & Passes  pages before you sign up to ensure the trip is right for you.

Each participant is responsible for their own safety and being prepared. Planning and preparation start with the 10 essentials  and staying up-to-date on road and trail conditions, permit requirements, party size limits, snowpack, wildfires, and weather.

Learn More