Ecofin US Renewables (RNEW ) has warned of a ‘material short-term impact on cash flows’ after a tornado in Texas last week damaged its one US wind farm accounting for over a third of the $102m portfolio.

The company said the tornado, which killed four and injured nine in west Texas on 21 June, had damaged five transmission poles at its Whirlwind Energy wind farm in Floydada and severely damaged the American Electric Power owned substation in neighbouring Matador, through which Whirlwind transmits electricity.

‘Due to the outage, the company has declared a force majeure event with Whirlwind’s offtaker, Austin Energy,’ it said in a statement to the stock exchange.

Expressing sympathy and condolences for those affected by what local officials in Matador have called an ‘unprecedented tornado’, the company said its fund manager Ecofin Advisors was working closely with Whirlwind’s asset and operations managers to put in place a plan to remedy the outage at the 59.8MW wind farm.

It was also working with its insurer to file claims for business interruption and repairs to the transmission poles.

‘Whether or not the company is able to recoup potential losses resulting from the tornado under its insurance policies or other contractual arrangements, the company expects the outage to have a material short-term impact on cash flows,’ it said.

As at 31 March, Whirlwind made up 38% of the investment company’s net asset value excluding debt or 24.5% of gross asset value including debt. It has seven other assets all of them solar.

The natural disaster is a challenge for the trust’s new fund manager Eileen Fargis who joined from InterEnergy Holdings (UK) last October after the original investment team behind its 2020 launch unexpectedly quit.

Although the outage will likely leave its dividends uncovered by earnings this year, shares in the dollar denominated 7.7% yielder were steady in early trading, slipping 0.7% to 68 cents.

In common with other renewables funds, which have tumbled as interest rates and government bond yields have surged, over one year the shares have shed 32% of their value to leave them 27% below NAV of 93 cents per shares.

That leaves the trust with a market value of £74m, making it by far the smallest in its peer group which could raise questions about its long-term viability.

Analysts at Peel Hunt, the trust’s corporate broker, this morning downgraded the stock from ‘outperform’ to ‘underperform’ noting that despite US government bond yields jumping from 1.5% to 3.7% since the start of last year, RENW had only lifted the discount rate with which its values its cash flows by 25 basis points, or 0.25%, to 7.5%.

In the absence of other factors, rising discount rates will lower a fund’s asset value, ‘adding further uncertainty to the likely trajectory of RNEW’s portfolio valuation, where the bulk of revenues to 2027 are fixed price in nature,’ said analyst Markuz Jaffe.